Relatives of Joseph Scott Williams said yesterday that he felt compelled to come to people's aid and that the woman accused of killing him at her town house in Dale City was a friend he was trying to help with financial problems.

John and Michelle Williams said their brother was frantically making calls to social service agencies on Tuesday on behalf of Danita Yvonne Corbin, saying that she needed money because her roommate had recently left without paying the rent. Williams, who had a mild mental disability, never suggested to anyone in his family that he felt threatened by Corbin, his siblings said.

Two days after he made the calls, Williams's charred and beaten body was found outside Corbin's town house, and Corbin, 28, and a 17-year-old Stafford County youth were arrested on charges of murder, robbery and abduction. Police say that after beating Williams, the two suspects stole his wallet, dragged him to a forested spot 60 feet behind the town house development and set his body on fire.

Corbin's attorney, Robert Horan, said yesterday that he had not yet spoken with her and could not comment on the case. In the criminal complaint filed against her in Prince William County Circuit Court, county police detective Ronald K. McClelland said Corbin "admitted to her involvement" when she was questioned by police. The 17-year-old suspect, whose name was not released, was charged as a juvenile.

Prince William Commonwealth's Attorney Paul B. Ebert said he is considering a charge of capital murder against Corbin, which would create the possibility of a death sentence if she were convicted. A murder charge can be upgraded to capital murder when combined with other felony charges.

In an interview at the Williams family's Dale City home, which is only three miles from Corbin's residence, Williams's relatives described him as someone who constantly sought to aid others, often helping total strangers whose cars had broken down.

"My brother always wanted to help people," said John Williams, 23. "And sometimes he didn't know--he would help too much."

Stafford County relatives of Corbin described her as an independent, hard-working woman who distanced herself from some of her family as an adult.

Marie Williams, a cousin, said she spoke to Corbin last week. "She was mostly wanting to talk about getting her house fixed up," Williams said. "If she was struggling, she'd never let you know she was struggling."

Family members said Corbin was born in the District but moved to Stafford County after her father was killed. Relatives said she grew up in Stafford and attended high school there.

Joseph Williams, 32, was a stout, redheaded man known for his neat attire and for walking around his neighborhood daily talking on his ham radio to others in a ham radio club. A 1981 accident, in which he was hit by a car while trying to cross the road, left him with limited peripheral vision, a slight limp and an inability to "handle stress very well," his brother said.

Because of this, his brother said, Williams switched jobs frequently, and his parents--Robert Williams, 59, a retired Navy man who now works for GTE, and Marjorie Williams, 59, a retired preschool teacher--supported most of his needs. Williams did not drive and lived with his parents.

Some of Williams's friends said that he and Corbin met at Northern Virginia Community College, which they both attended in the late 1980s and early 1990s. His friends said they did not know if the two of them had kept up through the years or only recently renewed their friendship.

Williams's brother said he recalled that a woman named Danita had called the Williams residence a number of times, and Corbin's neighbors said Williams often visited her town house.

According to Williams's brother and sister, he was supposed to attend a 7:30 p.m. service at the family church, Evangel Baptist, on Wednesday but never arrived.

Chung Park, an employee at a nearby K-7 Food Mart, which Williams visited almost daily, said Williams came into the store about 7 or 8 p.m. Wednesday. Park said Williams seemed upset as he told Park that a woman friend wanted him to lend her $1,500 to help her with her rent.

Park said that Williams then called police and that an officer met Williams outside the store and talked with him for 10 minutes. Williams later told Park that they had discussed the situation involving the woman and that the officer had said Williams should call him if any problems arose.

Kim Chinn, a Prince William police spokeswoman, said that she could not confirm this account but that there was a recent police report in which Williams complained of being threatened.

CAPTION: Danita Corbin, 28, is charged with murder in death of a disabled man.