When a friend of Jose Antonio Cruz's cousin immigrated to the United States from El Salvador about a year ago, Cruz not only went to pick him up at the airport, but gave him a place to live, clothes and food. He even helped him find jobs, though Cruz had never met the teenager before.

Cruz saw the teenager as part of his extended family, and he was happy to help an immigrant like himself.

The two became friends, and Cruz, also from El Salvador and older by about five years, became something of a father figure to the teenager, according to friends and relatives of both.

That friendship ended early yesterday morning when Cruz, 23, was stabbed to death. A D.C. homicide detective at the scene said the friend is a suspect, but police have not named him.

As of last night, no arrests had been made in the slaying.

Cruz "took him in, gave him food, clothes, a place to stay, and this is the thanks he gets, this is how he pays him back," said Jose Santo Laso, Cruz's uncle.

Police and witnesses said Cruz, the teenager and several other men were hanging out at a park at 13th Place and Peabody Street NW drinking beer. Cruz and his friend got into an argument because Cruz blamed the teenager for the incarceration of a friend of Cruz's in connection with a stolen car.

Witnesses said Cruz believed that the teenager had allowed the friend to get into a stolen car unknowingly. When the car was stopped by police, everyone ran, and only the unwitting friend was caught, witnesses said.

Raymond Melgar, who said he saw the stabbing, said Cruz and the younger man grappled hand-to-hand, with Cruz getting the better of it. At one point, he said, the younger man threatened Cruz with a screwdriver, but Cruz disarmed him. The man went into an apartment building and came out with a kitchen knife about eight inches long, witnesses said. Before Cruz could get away, he was stabbed in the heart, and his killer ran away, said Melgar and Adalberto Diaz, another witness.

Yesterday, Cruz's friends and family members gathered under a tree near where the stabbing occurred. Yellow police tape still lay on the ground near the site of the slaying. Other friends and family members gathered in the nearby apartment where Cruz's parents and three of his siblings live.

They said Cruz was an easygoing, intelligent young man who had come to the United States about 10 years ago. He worked as a carpenter and enjoyed drinking beer, going out dancing on weekends and playing golf -- a game he was introduced to by his boss.

Cruz, who went by the name Antonio, or Tonio for short, had been introduced to the teenager by a cousin, Justiniano Flores.

Flores said his friend lived with Cruz in Cruz's apartment for two or three months before setting out on his own. Even after the young man moved out on his own, he and Cruz remained friends.

Cruz's friends and family members said they couldn't recall the two fighting before yesterday.