Appellant was convicted of two counts of possession under the Federal Narcotics Laws. The issues raised on appeal concern the admissibility of narcotics seized by the police. Although appellant attacks the denial of a pre-trial motion to suppress, his primary target is the trial judge’s refusal to reconsider the suppression issue after a change in police testimony at trial.
Appellant testified at the suppression hearing that he was walking along the street in search of a taxicab at about 4 o’clock in the morning when a black unmarked Plymouth sedan stopped alongside him and two men in plainclothes stepped from the car; that one of them told him to “hold it”; that he was then searched, narcotics were uncovered, and he was charged with narcotics violations and vagrancy. If this version of the facts is accepted, appellant’s arrest was unlawful and the search invalid.
Two police officers, Jenkins and Whited, both testified, however, that appellant had abandoned the narcotics in a pile of wooden pallets in an alley within their eyesight and while fleeing their unmarked police cruiser. If the narcotics were thus abandoned there was no illegal seizure. But the remainder of the police testimony was inconsistent. Whited stated that Jenkins was driving the police cruiser; Jenkins said Whited was driving. Whited stated that they spotted appellant “just a short distance” into the alley off R Street and that he was walking away from the cruiser; Jenkins testified that appellant was “not anywhere near R Street in the alley but was toward S Street and was coming toward” them. Officer Whited said that they followed appellant in a northerly direction along the alley and that he turned left into an intersecting alley. Officer Jenkins’ testimony was the opposite.
Quite understandably, the suppression judge expressed concern over the numerous inconsistencies in police testimony and refused to accept the government’s characterizations of the inconsistencies as “slight” or “immaterial.” He nonetheless denied the motion to suppress, reserving to appellant the right to renew the motion at trial and offering to order a copy of the transcript of the hearing for the trial judge.
At trial, Officer Jenkins changed his testimony, bringing it almost into line with that of Officer Whited. When confronted with his earlier testimony, given at the suppression hearing, Officer Jenkins explained that he “had the facts of this case confused with another narcotics case involving a subject of similar circumstances in which an arrest was made just about twenty days prior to this one.” At the conclusion of Jenkins’ testimony, and again after Whited had testified in part, appellant’s counsel renewed his contention that the narcotics were illegally seized. He requested the trial judge to allow him to question Officer Whited out of the presence of the jury. The trial judge stated, “[Ajfter one judge has ruled on the motion to suppress evidence, I don’t usually hear it again. I let them rely upon the showing made at that time.” After reading the transcript of the pretrial hearing, the trial judge denied the motion to reconsider the question of admissibility of the narcotics on the sole ground that the suppression judge had held a “full and complete” hearing, and that his ruling was “the law of the case.” We think the trial judge erred.
A pre-trial ruling on a motion to suppress does not bind the trial judge in *1016all circumstances.1 New facts, new light on the credibility of government witnesses, or other matters appearing at trial may cast reasonable doubt on the pretrial ruling.2 It then becomes the duty of the trial judge to consider de novo the issue of suppression and, if necessary, hold a hearing out of the presence of the jury.3
The courts are particularly sensitive to new matters concerning a search incident to a warrantless arrest. A warrant requires a before-the-event justification which involves confirmation of legality by a judicial officer. When probable cause appears, a warrant is not required for an arrest in public, even where practicable.4 However, the police, who have the burden of showing that a warrantless arrest was valid,5 must take all reasonable steps to assure that their testimony accurately reflects what occurred.6 And the courts must “scrutinize more closely the testimony in cases involving warrantless arrests.”7
In the present case, doubts concerning the sufficiency of the police testimony came not alone from the inconsistency at the suppression hearing. The vagrancy charge against appellant lends support for appellant’s version of a search incident to an arrest rather than the converse. And it is difficult to understand the police testimony that appellant took flight upon seeing them, even though they were in plainclothes in an unmarked automobile. As the suppression judge realized, the government’s case on suppression was indeed a precarious one.
Then at trial came Officer Jenkins’ explanation that he had been confused. The Officer stated that he had made two arrests within twenty days involving “similar circumstances,” thereby inferring that the earlier arrest also involved flight of the suspect and abandonment of narcotics in an alley near R Street at about 4:00 A.M. At the very least, the Officer’s explanation amounted to an admission of carelessness and confusion at the suppression hearing. Even more importantly, if no such similar arrest occurred, it would entirely destroy the credibility of all the police testimony. We think his explanation, which stirred previous doubts and raised new ones, reasonably required inquiry and a fresh determination of the suppression issue. Accordingly, we remand the case for that purpose.8 If suppression is granted, a new trial will be ordered. If suppression is denied, then the judgment of conviction shall stand, subject to appeal.
So ordered.
. See, e. g., Cogen v. United States, 278 U.S. 221, 224, 49 S.Ct. 118, 73 L.Ed. 275 (1929); Gouled v. United States, 255 U.S. 298, 312-313, 41 S.Ct. 261, 65 L.Ed. 647 (1921); Anderson v. United States, 122 U.S.App.D.C. 277, 352 F.2d 945 (1965); see Jennings v. United States, 101 U.S.App.D.C. 198, 199, 247 F.2d 784, 785 (1957).
. See DiBella v. United States, 369 U.S. 121, 129, 82 S.Ct. 654, 659, 7 L.Ed.2d 614 (1962); “[T]lie legality of the search too often cannot truly be determined until the evidence at the trial has brought all circumstances to light.”
. See McNabb v. United States, 318 U.S. 332, 346, 63 S.Ct. 608, 87 L.Ed. 819, (1943).
. Ford & Kimble v. United States, 122 U.S. App.D.C. ___, 352 F.2d 927 (1965).
. See, e. g., Beck v. Ohio, 379 U.S. 89, 97, 85 S.Ct. 223, 13 L.Ed.2d 142 (1964); Wrightson v. United States, 95 U.S.App.D.C. 390, 392, 222 F.2d 556, 558 (1955).
. Cf. Ross v. United States, 121 U.S.App.D.C. 233, 349 F.2d 210 (1965).
. Jackson v. United States, 122 U.S.App.D.C. 324, 330, 353 F.2d 862, 868 n. 15 (1965).
. The District Court’s disposition on remand may make it unnecessary to decide appellant’s contention that the police testimony at the suppression hearing was “inherently incredible.” See Jackson v. United States, supra note 7.