A daring Sunday afternoon killing in front of a convenience store in Southeast last month was retribution against a man who wanted to quit a drug organization, a police investigator said yesterday.

The slaying of Vernon Page, 25, who was shot about 10 times as he walked out of a 7-Eleven on Sept. 2, occurred after he told a fellow drug gang member from the Trinidad section that he had had enough, said the investigator.

Yesterday morning, a suspect sought in connection with the shooting, which also wounded a bystander, surrendered to police. James Corbin, 19, was charged with first-degree murder while armed.

Homicide detectives identified Corbin, whose address is unknown, through a partial license tag number on a car.

The shooting occurred at 4:15 p.m. on the corner of 14th Street SE and Pennsylvania Avenue, steps from the Potomac Avenue Metro Station and in front of the 7-Eleven. Page bought a cupcake in the convenience store, walked out the door and was gunned down from behind, police said.

A 23-year-old woman standing nearby was shot in the leg. The woman, whose name has been withheld because she is a witness, was not seriously hurt, police said.

The investigator, who asked not to be identified, said that hours before the shooting Page had visited a fellow drug gang member to say he wanted out.