(dissenting). I depart from the majority because I conclude the defendant is entitled to an evidentiary hearing on the issue whether her plea was voluntary.
“In determining whether a ‘substantial issue’ meriting an evidentiary hearing under rule 30[1] has been raised, we look not only at the seriousness of the issue asserted, but also to the adequacy of the defendant’s showing on the issue raised.” Commonwealth v. DeVincent, 421 Mass. 64, 67 (1995), quoting from Commonwealth v. Stewart, 383 Mass. 253, 257-258 (1981). See generally Smith, Criminal Practice and Procedure *320§§ 1250-1260 (2d ed. 1983 & Supp. 1999). “It is elementary that a coerced plea is open to collateral attack.” Fontaine v. United States, 411 U.S. 213, 215 (1973). Huot v. Commonwealth, 363 Mass. 91, 96 (1973). Moreover, the defendant has made a strong showing that her plea colloquy did not reveal the participation of a person who exerted undue influence upon her. This is not a case where the defendant “is limited to [her] own plaintive allegations” and is unable to “corroborate them in a post-plea voluntariness hearing.” Commonwealth v. Foster, 368 Mass. 100, 106 (1975) (emphasis supplied). To the contrary, the defendant has from outside sources presented significant corroboration of her own allegations.
Although the voluntariness of a plea and the factual basis of the charge are distinct concepts, see Commonwealth v. Fernandes, 390 Mass. 714, 719 (1984), the latter can have an important bearing on the former. Just as the factual basis for a guilty plea (a requirement under Mass.R.Crim.P. 12[c][5][A], 378 Mass. 869 [1979]) “can be of significant assistance to the judge in the performance of his duty to ensure that the plea is voluntarily and intelligently made,” Commonwealth v. Morrow, 363 Mass. 601, 608 (1973), a showing that significant facts supporting the plea are false can, and here does, raise the substantial question whether the defendant voluntarily entered her plea.
The supplementary materials2 cast doubt on the veracity of statements made by the defendant to the police on October 17, 1991,.which were relied on by the Commonwealth as the factual basis for the plea. They also lend credence to the claims in the defendant’s affidavit that the plea was extracted from her by undue pressure from her former boyfriend, Paul Haynes.
1. Facts presented at plea hearing. The questions by the police and the defendant’s answers, reproduced in the margin3 *321and read by the assistant district attorney at the plea colloquy, set forth that on October 17, 1991, the defendant stated that there was no one else in the house when the defendant pushed Garrett on the date of his death, that she had also pushed Garrett in the same way four or five other times, that these punishments had begun in September,4 and that there was no one else *322present when they took place. These statements will be shown to be open to serious question.
2. Supplementary materials. The supplementary materials will be described in some detail. That significant portions of the materials relate to Haynes’s conduct with other women and children does not diminish their strength. See Commonwealth v. Gallison, 383 Mass. 659, 672-673 (1981); Commonwealth v. Odell, 34 Mass. App. Ct. 100, 103-104 (1993).
(a) Evidence at Haynes’s August, 1994 trial. The partial transcript of Haynes’s trial, in which he was convicted of the unrelated charges of forcible rape of a child and indecent assault and battery of a child under fourteen, provides a chilling picture of Haynes.5 Accompanied by the present defendant, Deborah Conaghan,6 Haynes moved into the home of the victims, Joyce and James, and their mother in January or February 1992. Joyce was then eleven, and James was nine years old.
Joyce’s testimony was damning. Rebekah, the children’s mother, began to hit them at the time of Haynes’s arrival. Haynes hit them often, sometimes with a belt on their naked bodies. On several occasions he made them kneel on a pencil for hours in a comer. James received the brant of Haynes’s ire, and was hit at least five times a week. The children could not go to the bathroom without Haynes’s permission, which was often withheld. Haynes forced James to spread his legs apart and then kicked him in the groin. He also directed Joyce to kick James in this manner. He punched James in the stomach with a closed fist “to toughen [him] up.” In front of Joyce, on more than one occasion, Haynes put a cigarette lighter under James’s penis and thereafter it “looked crispy like. . . . Not like skin, but like burnt paper.” He also grabbed James by the hair on the back of his neck and lifted him up by his hair. According to Joyce, James was “[s]cared. He was real quiet. He would stay in his room most of the time.” He did what Haynes said to do *323and never defied him.7
Joyce wanted to be Haynes’s daughter and had a sexual relationship with him. Haynes had told her that he was a Cherokee Indian and, in that tradition, in order to be his daughter Joyce had to have sex with him. Rebekah knew about some of the beatings and about the sex, and even told Joyce that it was all right for her to have sex with Haynes. Despite his behavior, Joyce trusted Haynes and did not want him to go to jail. For this reason, she never told anyone what went on in the household until she was moved to a foster home.
Rebekah, who was charged with rape of a child and indecent assault of a child under fourteen (Joyce was in each instance the victim), testified that soon after Haynes returned to the apartment, see note 6, supra, her mother became sick. She left Joyce and James with Haynes. In her absence, he changed the locks to the apartment and would not let her return to reside there. He let her in, however, to cash her welfare checks, the largest portion of which, together with food stamps, she gave to Haynes. Although she did not want to do so, Haynes persuaded her in December, 1992, to make him the guardian of her children. During her visits she observed Haynes abusing them. He was very severe with James. He made both children kneel on pencils on the kitchen floor with no clothes on. Because of her fear of Haynes she did not object to his invoking an alleged Indian tradition that, for a girl to be someone’s daughter, the father had to be the first person to have sex with her. She saw Joyce perform fellatio on Haynes and also saw her haying intercourse with him. Rebekah wanted to stab Haynes but refrained out of fear. She thought he would overpower her and that she and the two children “would end up dead.” Accordingly, she did nothing.
Haynes would not permit Rebekah to speak to the children alone. When asked why she did not interfere with Haynes’s treatment of the children, she answered because of her fear of him. Although he did not directly threaten her, his indirect threats were sufficient “to put a scare” in her. He told her he had “a friend Tony that took care of his problems or got rid of *324people [who] caused problems for him.” He also told her he had a gun in his briefcase. She didn’t dare tell anyone. “I didn’t want to put anybody at risk for being eliminated if I reported him.”
James’s testimony confirmed Joyce’s and was even more graphic as to the abuse he suffered at the hands of Haynes. He never told anyone because of fear that Haynes would “[t]ry and kill me or something.”
Deborah Conaghan, the present defendant, also testified at Haynes’s trial.8 She told how he kissed and hugged Joyce and made her lift up her shirt. He hit both children with a belt with clothes off. Haynes showed Conaghan James’s bruising to humiliate him. Conaghan was asked about Tony. He was described to her by Haynes as “[v]ery mean and just that when he wanted something he got it and didn’t care how he got it.” She testified that Haynes had shown her a gun. On cross-examination, when asked if she still loved him, she answered, “In a sense because of what we shared, yes.”
Another former girlfriend of Haynes who met him in December, 1992, also testified. She confirmed the cruelty to James whom she described as always “walking on eggs.” She never disclosed Haynes’s treatment of the children because she was afraid. Haynes had told her about Tony who was Haynes’s associate. “[T]here’s almost like a vigilante-type thing. They took care of people who would hurt other people. They had this, like a warehouse that they would take people to and beat them up.” Asked if Haynes had threatened her with Tony, she answered, “Not in so many words. What he would say is if anyone crossed him that he and Tony would, you know, take care of that person.” The witness testified she was afraid of Tony and of Haynes.
(b) Investigative reports from the district attorney’s office. Prior to Haynes’s trial, the district attorney’s investigations produced reports of other abusive behavior by Haynes. Some of these reports accompanied the defendant’s motion and included *325the following information.9 A friend of Rebekah, “D,” recounted that Rebekah feared Haynes and was controlled by him. Once “D” saw Haynes force Rebekah to strike James. Had she not done so, Haynes would have struck him. Haynes also made Rebekah write a letter ending her relationship with “D.”
“S,” who met Haynes in May 1993, married him about a month later, and broke up with him in July, 1993, reported that Haynes threatened that if she or anyone crossed him he had ways of taking care of such persons. Haynes had a gun and claimed to know a man named Tony who would take care of any problems if she did not cooperate.
Two other women, “W” and “L,” recounted violent relationships with Haynes. “W,” who had a daughter with Haynes, agreed to give the daughter up after Haynes worked on her for several months and threatened that, if she did not sign adoption papers, he would have her killed. She eventually moved into a motel with “L,” a new girlfriend of Haynes, who had an eighteen month old son. She saw Haynes abusing the child — “she saw [Haynes] throw [him] into the shower.” Once, when the child was being potty trained, Haynes took the child and “shoved his whole body into the toilet.” When the child tried to get out, Haynes slapped him across the face. “W” saw Haynes beat the child every day for two or three weeks and also saw him hit the child with a sneaker. Haynes threatened “W” that if she told anyone what was going on, she would be killed by some of his friends in the Mafia.
Eventually “W” and “L” went to the police. Thereafter, once while “W” was walking, Haynes drove onto the sidewalk and sideswiped her with his car. She had seen him coming and had jumped, but the car nevertheless hit her foot and ankle. “W” stated that Haynes was charged with abuse of “L’s” child and that she (“W”) had testified at his trial.
“L” (and also her mother) confirmed much of what “W” had related to the investigator.10 “L” stated that Haynes on occasion had threatened her with a gun, and had told her he was connected to the mob. He indicated if she told anyone that he had assaulted her, he would kill both her and her son. She was scared and felt threatened the entire time she was with him.
*3263. Adequacy of the defendant’s showing. Haynes, as depicted in the foregoing materials, was a man who was able to exert extraordinary power over women and children. Through intense fear, sometimes mixed with romance, he induced women and children to do his bidding, however cruel it might be.
The extensive evidence of Haynes’s physical abuse of children, particularly boys, as shown by his treatment of James and “L’s” eighteen month old child, creates doubt as to the veracity of at least some of the evidence introduced at the defendant’s plea colloquy. That the defendant acted without Haynes, and that he, although living with her, was never present during any of the abusive episodes is simply not credible. Nor is it credible that such punishments were initiated and performed solely by the defendant. If, as seems likely, the defendant covered up for Haynes, there is a serious question as to why. In this context, and in light of Haynes’s behavior with other women and their enormous fear of him, the defendant’s claim in her affidavit that she was instructed to plead guilty by Haynes and was afraid not to do so becomes plausible. That claim as set forth in her affidavit was as follows:
“51. During the plea hearing, the judge asked me if anyone had forced me to plead guilty. I answered no. However, Haynes had pressured and warned me to plead guilty. Because I thought that I loved him and feared the consequences if I did not plead guilty, I chose to remain quiet about Haynes’[s] involvement in Garrett’s death and the pressure which he exerted on me to plead guilty.”
The defendant’s fear is also recounted in the following paragraphs:
“26. At the beginning of my relationship with Haynes, he informed me that he worked for an individual named ‘Tony’ who was affiliated with the Mafia. Haynes stated that Tony would take care of any problems that Haynes had. Subsequently, when I did not obey Haynes or displeased him in any way, he threatened me by making reference to Tony.
“27. I also learned that Haynes owned a handgun. I observed it while I was living with Haynes. Because I believed Haynes’[s] statements about Tony and knew that *327Haynes owned a firearm, I feared the consequences of upsetting or displeasing him.”
In rejecting the defendant’s affidavit as “untrustworthy,” the majority lay stress on the statement she gave to the police admitting that she pushed Garrett to the floor on the day of his death and on the admission in her affidavit that she participated in abusing Garrett. In her affidavit, however, she also relates that she was instructed to strike Garrett on his penis with a spoon and when she refused, “Haynes grabbed a spoon and struck Garrett on his penis.”11 It is significant that one of Rebekah’s friends told the district attorney’s investigator that Haynes forced Rebekah to strike her son, and, had she not done so, he would have struck him. It is not too great an inference to assume that Haynes would have hurt the child with even greater force or might have struck Rebekah, if she had refused. The actions of the defendant are not, however, presently at issue.12 What is before us is whether she has made an adequate showing that her guilty plea was not voluntary so as to entitle her to an evidentiary hearing on that question.
*328Another reason the majority is unpersuaded is the length of time between the defendant’s plea and her motion to withdraw it — more than four years. An examination of the defendant’s medical records at M.C.I. Framingham provides at least a partial explanation for her delay in asserting her contentions. The numerous notes from her mental health counselor indicate that prime problems addressed in therapy were the defendant’s inability to assert herself and recognize her own needs, and the need to decrease her “people pleasing behavior (especially saying no when appropriate).” The delay could be explored at a hearing.
In sum, the necessary factual determinations cannot be made on this record. Questions of credibility remain to be resolved by an evidentiary hearing. See Ciummei v. Commonwealth, 378 Mass. 504, 510 n.9 (1979) (“if a defendant asserts that despite a seemingly adequate exchange there was coercion, mental incompetency, or other factors that belied the record showing ... a [postconviction] proceeding would be perforce appropriate”). See also Fontaine v. United States, 411 U.S. at 215, where the Court in requiring such a hearing stated, “The objective of Fed. Rule Grim. Proc. 11, of course, is to flush out and resolve all such issues, but like any procedural mechanism, its exercise is neither always perfect nor uniformly invulnerable to subsequent challenge calling for an opportunity to prove the allegations.”13
Rule 30(b) of the Massachusetts Rules of Criminal Procedure, 378 Mass. 900 (1979), which is applicable when a defendant seeks to withdraw a plea, provides in relevant part: “The trial judge upon motion in writing may grant a new trial at any time if it appears that justice may not have been done.”
As pointed out in note 4 of the majority opinion, ante at 310, the Commonwealth did not object to the reliability of any of the defendant’s documents and cannot object now.
Question [relating to events of October 12, 1991]: “When you pushed him down, did Garrett’s head hit anything else other than the floor?”
Answer: “I can’t recall whether he hit anything else, he could have hit the hutch that is in the kitchen.”
Question: “Was anyone else in the house?”
Answer: “No.”
*321Question: “You did this to punish Garrett because he threw up?”
Answer: “Yes.”
Question: “Did you ever do this before?”
Answer: “Yes, it could have been four or five times.”
Question: “What happened?”
Answer: “Garrett was disobeying or not listening to me so instead of hitting him I kept pushing him onto the floor. I pushed him two to three times and every time I pushed him he got up and I pushed him again.”
Question: “What did he hit his head on when this happened?”
Answer: “The floor or the hutch."
Question: “Where did this usually take place?”
Answer: “In the kitchen.”
Question: “Was anyone else there when this happened?”
Answer: “No, just myself.”
Question: “After you started pushing him, did he start having headaches?”
Answer: “Yes.”
Question: “About when did you start pushing him down?”
Answer: “Sometime around the beginning of September. About that time he started developing a lazy eye.”
Question: “Did he start vomiting a lot about this time?”
Answer: “It would be off and on.”
Question: “Why did you push him?”
Answer: “Because I did not want to hit him and I did not want to abuse him, but in the end I did.”
The abuse thus began when Haynes first came in contact with Garrett. Garrett returned to the defendant’s residence at the end of August, 1991, after spending the summer in New Jersey. The defendant’s relationship with Haynes began during the summer of 1991.
Our opinion, Commonwealth v. Haynes, 45 Mass. App. Ct. 192 (1998), affirming those convictions, had not been issued at the time of the defendant’s submissions in support of her motion. The facts as stated in that opinion provide relevant background to my discussion. I refer to the fictitious names of the victims used in that opinion.
Haynes and Conaghan moved out in May, 1992. As set forth in Conaghan’s affidavit in this case, she turned herself in to the police on May 6, 1992. Haynes moved back to the victims’ apartment about six weeks later.
The foster mother with whom the children were placed noticed “their intense need to please and do the right thing and concern that if they didn’t that they would be asked to leave, or they didn’t know where they would go. They were really just very frightened about everything.”
When questioned whether she was threatened by Haynes with Tony she answered, “No.” Before Conaghan testified, the assistant district attorney informed the judge that Conaghan was appealing her sentence (not withdrawing her plea) and was concerned that her testimony might adversely affect her appeal.
The record discloses the names of the persons interviewed by the investigators. It is unnecessary to reveal the names in this account.
In addition, the reports described physical abuse of women as well as rapes by Haynes.
In this context the last answer to the police read at her plea hearing and quoted in note 3, supra, takes on additional poignant meaning — “Because I did not want to hit him and I did not want to abuse him, but in the end I did.”
While her actions were certainly not those expected of a parent, if a new trial were granted, it would be open to the defendant to argue that undue pressure was exerted upon her, that is, she was coerced to participate in pushing her son. In this connection, G. L. c. 233, § 23F, as inserted by St. 1996, c. 450, § 248, contrary to the interpretation of the majority, would permit her, if she alleges a defense of coercion, to introduce “evidence by expert testimony regarding the common pattern in abusive relationships; the nature and effects of . . . psychological abuse . . . , including how those effects relate to the perception of the imminent nature of the threat of death or serious bodily harm; . . . and evidence whether the defendant displayed characteristics common to victims of abuse.” See United States v. Marenghi, 893 F. Supp. 85, 95 (D. Me. 1995) (expert testimony may explain “how a reasonable person can nonetheless be trapped and controlled by another at all times even if there is no overt threat of violence at any given moment”). See also Commonwealth v. Crawford, 429 Mass. 60, 66 (1999) (defendant entitled to place evidence through her expert that she was incapable of refusing to answer questions put to her by police); Commonwealth v. Goetzendanner, 42 Mass. App. Ct. 637, 640, 642 (1997) (victim’s vacillating behavior toward defendant-abuser proper subject of expert testimony). That a new trial might result in the defendant’s conviction of a lesser crime, or lead a judge to impose a sentence less than the current one to M.C.I. Framingham of not less than twelve years nor more than eighteen years, are possibilities if the facts as alleged in the defendant’s affidavit turn out to be credible. See United States v. Johnson, 956 F.2d 894, 902-903 (9th Cir. 1992).
But see Commonwealth v. Moreau, 30 Mass. App. Ct. 677, 683 n.3 (1991), cert. denied, 502 U.S. 1049 (1992), noting (prior to the amendment of 28 U.S.C. § 2255 by Pub. L. No. 104-132 [1996]) that the Federal statutes “facially are more generous in favoring hearings than is Mass.R.Crim.P. 30(c)(3), 378 Mass. 901 (1979).”