Appellant Rebecca Smith (Rebecca) was convicted of murdering her husband during the commission of an armed robbery and sentenced to death. We reverse the conviction and remand for a new trial.
FACTS
On Friday, July 14,1989, Harold Smith (Harold), the victim, left his home in Laurinburg, North Carolina, for Myrtle Beach. There, he stayed in a mobile home belonging to Rebecca’s mother. On the following Monday, Rebecca attempted, unsuccessfully, to call Harold several times; when she could not reach him by Tuesday, she contacted the North Myrtle Beach police department.
In response to her call, Officer Asa Bailey went to the mobile home on Tuesday afternoon. He noticed the front door appeared to be pried open and, when he investigated further, discovered Harold’s dead body in the front bedroom.
The pathologist testified that Harold died from blunt trauma to the head with associated massive injury to the underlying brain, an injury consistent with being struck on the forehead with a blunt instrument, such as a baseball bat. He estimated the time of death to be 2:00 a.m., Monday, July 17, 1989.
The State’s case was, primarily, based upon the testimony of Hank Locklear, Rebecca’s nephew. His testimony at trial, is summarized:
*444On Sunday night, July 16,1989, Hank was at Rebecca and Harold’s home in Laurinburg, North Carolina. Billy McGee (Billy), an alleged paramour of Rebecca’s, came over and, along with Rebecca and her son, Brian, used cocaine. About thirty minutes later, Hank, Billy, Rebecca, and Brian drove to Myrtle Beach, arriving at approximately 2:30 a.m. They went first to the pier, then to the trailer where Harold was staying. While Hank and Billy remained in the car, Brian and Rebecca knocked on the trailer door and Harold let them in. Rebecca was carrying a baseball bat.
About one hour later, Rebecca came running out, telling Billy and Hank to come into the trailer, that she had killed Harold. Hank saw Harold lying on the bed in a pool of blood, calling out for Rebecca. After Rebecca struck Harold with the baseball bat, Brian took the bat and hit him again to “make sure-that he was dead.” Billy then took the bat, hitting the trailer door to give the appearance of a break-in. Hank, frightened, returned to the car. On the return trip to Laurinburg, Rebecca put on Harold’s diamond horseshoe ring and rifled his wallet. Billy was wearing Harold’s watch.
Billy’s testimony at trial was, essentially, the same as Hank’s; however, he testified additionally that, after the murder, Brian removed Harold’s ring and wallet and gave them to Rebecca. At Rebecca’s direction, Billy picked up the watch. He stated that, as they returned to Laurinburg, the money was removed from the wallet which, along with the baseball bat, was thrown over a bridge. Later, Rebecca gave the watch and ring to her “root worker.”
Brian’s testimony for the defense gave an entirely different version of the events from that of Hank and Billy. According to Brian, on the night in question, his mother, ill with vertigo, never left Laurinburg; only he, Hank, and Billy went to the Beach for the purpose of obtaining salt water which Hank needed for his witchcraft. When they arrived at the trailer, Brian and Hank went to visit with Harold, while Billy stayed in the car “shooting up” cocaine. After Harold was asleep, Billy went into the trailer with the baseball bat and killed Harold.
*445Rebecca testified in her defense at trial. She corroborated Brian’s testimony, claiming she was never at Myrtle Beach, but was in Laurinburg ill with vertigo. She admitted having given earlier statements which placed her at Myrtle Beach, but testified they were given only to protect Brian.
The jury convicted Rebecca of murder in the commission of armed robbery and imposed the death sentence.
Billy, Hank, and Brian all pled guilty to various charges and were sentenced as follows: (1) Hank, pleading guilty to grand larceny and accessory after the fact, was sentenced to concurrent ten-year terms; (2) Billy, pleading guilty to criminal conspiracy, obstruction of justice, accessory after the fact of murder and grand larceny, was sentenced to 35 years; (3) Brian, pleading guilty to conspiracy, obstruction of justice, and two counts of accessory after the fact of murder, was sentenced to 35 years.
ISSUES
1. Was evidence of alleged cocaine use by Rebecca at previous times in the past erroneously admitted at trial?
2. Was it error to exclude Hank Locklear’s prior statement?
DISCUSSION
1. Evidence of Prior Cocaine Use
At trial, the following testimony of Billy was admitted 1 concerning Rebecca’s use of cocaine:
(1) Testimony of Billy that, at an unspecified time prior to the murder, he and Rebecca smoked cocaine obtained by trading pistols belonging to Harold;
(2) Testimony of Billy that, upon arriving at Myrtle Beach, Rebecca requested that he wait at the pier while she went to see Harold; however, he refused because she had “dropped me [Billy] off before and left me beside the road two and three hours at a time while she was going to get cocaine.”
We hold that this testimony was irrelevant to establish the crime at issue and was so unduly prejudicial as to constitute reversible error.
*446It is well settled that evidence of other crimes is incompetent to establish the crime at issue unless it tends to show: (1) motive; (2) intent; (3) the absence of mistake or accident; (4) a common scheme or plan; or (5) the identity of the perpetrator. State v. Lyle, 125 S.C. 406, 118 S.E. 803 (1923).
Moreover, in State v. Coleman, 301 S.C. 57, 389 S.E. (2d) 659 (1990), we held that, where the only function of evidence concerning the defendant’s use of illegal drugs “was to demonstrate [defendant’s] bad character and social irresponsibility,” the admission of such evidence was legal error. 301 S.C. at 60, 389 S.E. (2d) at 660. See also State v. Bolden, 303 S.C. 41, 398 S.E. (2d) 494 (1990). Further, evidence of drug use is incompetent to establish motive for a crime or the state of mind of the defendant where the record does not support any relationship between the crime and the drug use. Id.
We reject the State’s contention that Billy’s testimony was relevant to establish motive. Nothing in the record indicates a connection between the murder and Rebecca’s use of cocaine. Rather, Billy’s testimony about Rebecca’s drug use at unspecified times prior to the murder served only to discredit her character and portray her as a miscreant reprobate. This does not fall within the exceptions of Lyle, swpra, and is impermissible under our holding in Coleman, supra.
The dissenting opinion, which upholds Billy’s testimony under the res gestae exception, has misconstrued our prior case law. The South Carolina cases cited by the dissent allow evidence of another crime only when the other crime “had a direct bearing on and related to the commission of the [later crime].” State v. Johnson, — S.C. —, 410 S.E. (2d) 547, 552 (1991), cert. denied — U.S. —, 112 S.Ct. 1691, 118 L.Ed. (2d) 404 (1992). It is noteworthy that in all these cases the other crime also established motive, identity, and/or the state of mind of the defendant, thereby attesting to its relevancy.
Billy’s explanation as to why he and Rebecca argued on the night of the crime was not, as contended by the dissent, “part and parcel” of the subsequent murder of Harold. See State v. Brooks, infra. (Where defendant assaulted two women, one assault “was so inextricably interwoven ... it was, in effect, all one transaction.”) Rather, the two *447events are totally unconnected. Moreover, the prior incident of Rebecca smoking cocaine at an unspecified time was certainly not contemporaneous with Harold’s murder. As in State v. Bolden, supra, the defendant’s prior drug use, unrelated to the crime at issue, should have been excluded.
Finally, the prejudice of this testimony was heightened when the State employed it to impeach Rebecca’s character witnesses and, in closing argument, referenced her drug use. The testimony in this case produced diametrically opposite versions of what occurred, so that witness credibility was crucial to the jury’s determination of who and what to believe. The “prior cocaine use” testimony was so destructive to Rebecca’s character, hence her credibility, that it cannot be held harmless error or cumulative. State v. Outlaw, — S.C. —, 414 S.E. (2d) 147 (1992).
2. Hank’s Prior Statement of August 8,1989
On August 8, 1989, Hank made a voluntary oral statement of Officer Floyd, identifying Billy as the killer. In a subsequent statement of March, 1990, Hank changed his story, stating that Rebecca and Brian murdered Harold. In his testimony at trial, he reaffirmed that Rebecca and Harold had committed the crime.
Defense counsel sought to introduce a transcription of the earlier August 8 statement. The trial judge held it inadmissible on the ground that Hank was unable to identify it due to his inability to read. Although defense counsel was permitted to cross-examine Hank about the prior inconsistent statement, he was not permitted to introduce it into evidence.
Later, in an effort to have the statement admitted, defense counsel questioned Detective Floyd concerning its contents. The Solicitor’s objection on the ground of hearsay was sustained.
Rebecca argues it was error to exclude Hank’s August 8 statement as hearsay, contending that the statement itself was essential to reveal all of the inconsistencies in Hank’s later statement and his testimony at trial. We agree.
It is well settled that evidence is not hearsay unless offered to prove the truth of the matter asserted. State v. Sims, 304 S.C. 409, 405 S.E. (2d) 377 (1991), cert. denied Sims v. South Carolina, — U.S. —, 112 S.Ct. 1193, 117 L.Ed. *448(2d) 434 (1992). Moreover, prior inconsistent statements are admissible as substantive evidence “when the declarant testifies at trial and is subject to cross examination.” State v. Copeland, 278 S.C. 572, 581, 300 S.E. (2d) 63, 69 (1982), cert denied. 460 U.S. 1103, 103 S.Ct. 1802, 76 L.Ed. (2d) 367 (1983).
Since the purpose of questioning Officer Floyd about the contents of Hank’s prior statement was impeachment, not to prove its truth, it should have been admitted.
Further, we agree with Smith that the exclusion of the prior statement cannot be considered harmless error. It is clear from the August 8 statement that Hank’s implication of Rebecca in the murder was, arguably, induced by the police officer’s leading questions.1 Additionally, many inconsistencies could not be fully developed by cross-examination, absent the statement itself.
Here, the credibility of witnesses was crucial to both prosecution and defense; the jury should have been permitted to examine the prior inconsistent statement in its entire text. Exclusion of the statement was reversible error.
The remaining issues from the guilt phase of the trial are affirmed pursuant to Rule 220(b)(1), S.C.A.C.R. Since we reverse Smith’s conviction, we do not address the sentencing phase issues.
Reversed and remanded.
Harwell, C.J., and Finney and Moore, JJ., concur. Toal, J., dissents in separate opinion.The following excerpt graphically illustrates the role that leading questions played in Hank’s statement:
HANK: From what I seen it was—
FLOYD: From what you saw, you saw it was a prearranged signal that I will cut the lights off, this is Rebecca, she goes in, she cuts the lights off and then that is some kind of signal for Billy Ray to go in — is that what you’re telling us?
HANK: Yes sir.