Mark Powell, 19, who worked at Wendy's to be able to buy the latest fashions, left the fast-food restaurant shortly after 9:30 p.m. Wednesday to walk to his Fort Washington home scarcely two blocks away.

Powell never arrived. A few minutes later the telephone at his home rang and, almost simultaneously, there was a knock at the door, family friend Theresa Hailstalk said yesterday.

The management at Wendy's was calling to say Powell had been seriously injured. The neighbor at the door said he feared the Powell had been shot.

Hailstalk said she and Powell's father, Russell, ran to the recreation center in the 6200 block of Caryhurst Drive where a yellow police tape prevented them from reaching the body lying in the shadows. They waited, fearing the worst. In time, Hailstalk said, a detective showed Powell's father a photograph. "We just hoped it wouldn't be true," said Hailstalk, "but it was Mark."

Mark Powell was the third homicide victim to die Wednesday in Prince George's County. Shot once in the chest, he was the victim of an apparent armed robbery, police said.

Jose Antonio Granados, 37, of the 6700 block of New Hampshire Avenue, Hyattsville, died shortly after midnight Wednesday at Washington Hospital Center of stab wounds he suffered during a fight on Aug. 31 in the 7900 block of 15th Avenue, police said.

Minutes before Powell was shot, Prince George's County police found Guy Eldridge Streat, 24, lying in the high grass in the 4600 block of Suitland Road. Mortally wounded and bleeding heavily, Streat, who lived in the 1900 block of Brooks Drive in Suitland, told officers that his girlfriend had stabbed him during an argument, police said. He died a short time later at Prince George's Hospital Center, police said.

Marie A. Overton, 24, of the 4700 block of Homer Street in Suitland, was charged yesterday with first-degree murder in Streat's death, police said. She is being held without bond in the county jail.

Police said that Powell and a co-worker were walking to Powell's home when they were accosted by four youths who demanded money. Hailstock said that Powell's companion told the family that Powell had forgotten his house key and was turning back to the restaurant when the four appeared, demanded money and shot without warning. He saw a figure in the shadows of the recreation center.

Powell thought he recognized the youth and called out his name, Hailstock said. The man told Powell that he was mistaken, and at that moment, three other young men emerged from the shadows, Hailstock said. The men asked for money, Hailstock said, and then, without warning, shot Powell in the chest.