BELL, Justice.

Gary Best was convicted of the malice murder of Thomas Anthony Moore, and was sentenced to life imprisonment. He was also convicted of, and sentenced for, the aggravated assault of Earl Graham, Sr.; possession of a firearm by a convicted felon; possession of a firearm during the commission of a felony (the murder of Moore); and possession of a firearm during the commission of a felony (the aggravated assault of Graham). Best appeals, and we affirm.

1. Considered in the light most favorable to the verdict, the evidence showed that on the afternoon of December 4, 1988, the appellant (a convicted felon), Charles Davis, and Diallow Johnson drove by a group of persons at a street intersection and fired shots into the group in an attempt at revenge for an altercation that occurred the previous night. One of the shots struck Moore, who was killed, and another shot struck Graham, who was wounded. We find the evidence of appellant's guilt was sufficient to satisfy the standard of Jackson v. Virginia, 443 U.S. 307 ( 99 S.C. 2781, 61 L.Ed.2d 560) (1979).

2. Appellant contends the trial court erred in denying his motion for new trial with respect to an allegation by appellant that his trial counsel was ineffective. We find no error.

Appellant asserts trial counsel erred by failing to secure the testimony of an alibi witness. Our review of the evidentiary hearing on effectiveness shows appellant did not satisfy the standards of Strickland v. Washington, 466 U.S. 668 ( 104 S.C. 2052, 80 L.Ed.2d 674) (1984) and Smith v. Francis, 253 Ga. 782 (1) ( 325 S.E.2d 362) (1985), in this regard. Perkins v. State, 260 Ga. 292 (2) ( 392 S.E.2d 872) (1990); Schirato v. State, 260 Ga. 170 (6) ( 391 S.E.2d 116) (1990). The remaining two grounds for appellant's assertion of ineffectiveness were not raised during the evidentiary hearing, and hence will not be considered on appeal.

3. Appellant, who was tried jointly with Davis, contends the trial court erred by failing to grant his motion to sever his trial from the trial of Davis. We find no error. Satterfield v. State, 256 Ga. 593, 595-597 (3) ( 351 S.E.2d 625) (1987).

4. The trial court did not err by admitting into evidence certified copies of felony convictions of appellant. The state was not required to show the validity of the prior felonies, as they were introduced to prove a necessary element of the crime of possession of a firearm by a convicted felon. Scott v. State, 250 Ga. 195, 198 (1) (d) ( 297 S.E.2d 18) (1982).

5. There is no merit in appellant's contention that the court erred by charging the jury that witnesses are presumed to speak the truth. Noggle v. State, 256 Ga. 383 (4) ( 349 S.E.2d 175) (1986).

6. We find no error in the trial court's imposition of two separate sentences for the two convictions of possession of a firearm during the commission of a felony, as one conviction was based on the murder of Moore and the other conviction was based independently on the aggravated assault of Graham.

7. Appellant's enumeration that the court erred by instructing the jury on conspiracy is without merit. Thomas v. State, 255 Ga. 38 (2) ( 334 S.E.2d 675) (1985).

Judgment affirmed. All the Justices concur.

BELL, Justice.

DECIDED MARCH 15, 1991.