A D.C. Superior Court jury yesterday found two Washington men guilty of murder and armed robbery in the killing of a "Good Samaritan" bank customer who tried to foil the holdup of a downtown Washington bank last year.

The jury deliberated less than two hours before finding David W. Basnight, 23, of 4046 Gault Pl. NE, and Evans A. Turner, 32, of 1732 S St. SE, guilty of killing the customer, John David Bowen, 30, who was making a deposit at the First American Bank branch at 13th and G streets NW at the time.

Bowen, who worked for McCallum Sauber florist wholesalers at 1314 I St. NW and was making a deposit for the firm, reportedly had been robbed and beaten on an earlier occasion. He went to the bank armed with a .25-caliber pistol.

The prosecutor, assistant U.S. Attorney F. Joseph Warin, told the jury that Bowen, realizing a robbery had occurred, followed Basnight to the door and ordered him to stop. Witnesses testified that the two men fired simultaneously. Bowen fired twice, hitting Basnight once in the jaw. Basnight fired a 38-caliber revolver three times, hitting Bowen in the head and arm.

Warin said Basnight, whose jaw was broken by the bullet, stood over Bowen as he lay on the floor and shot him two more times in the back.

Basnight, who had moved to Washington from North Carolina only seven months before the shooting, testified in his own defense. He contended that he fired at Bowen in self defense, that he had given up, had his hands up and was asking Bowen not to shoot when Bowen started firing. He denied that he shot Bowen twice in the back.

Basnight, who can barely read or write, said Turner was not the man who Warin called the "director" of the holdup. Warin said Turner assisted Basnight in the robbery by writing a note for him to hand to the teller along with a paper bag, then waited outside while the robbery occurred.

But during the six-day trial, government handwriting and fingerprint analysts testified that the handwriting on the note -- which read:"I want it all or I'll kill you" -- matched Turner's, and that his fingerprints were found on the note.

Judge Annice L. Wagner said yesterday that she would sentence Basnight and Turner on Feb. 10. A first-degree murder conviction carries a mandatory sentence of 20 years to life. Armed robbery is punishable by a prison term of 15 years to life, although under D.C. law, that sentence would run concurrently with the sentence for murder.