Jagjit Matta wavered for a heartbeat when reminded of claims by Arlington County prosecutors that they have overwhelming evidence fingering his son Chander as the killer of three Washington area prostitutes.

"He's not convicted yet," Matta finally said. "Nothing is proven. At this point, he is innocent until proven guilty. That is why we have a law."

His salt-and-pepper hair is neatly parted and combed, and his hands nervously work as he talks. On the outside of a pale pink shirt, Matta wears a locket bearing the picture of his spiritual leader, to whom he said he prays "every morning and every evening to give me strength and to give {Chander Matta} strength" during the ordeal.

A week ago, life for the Matta family was a model of American normality: two sons, a house in the suburbs, a close-knit circle of family and friends.

But since his son was arrested last Sunday and charged with Sherry K. Larman's death, the days have been filled with anguish, Jagjit Matta said in an interview yesterday.

Prosecutors in Arlington County have said they will seek to indict his son tomorrow in the slayings of two other prostitutes, whose deaths occurred over the Memorial Day weekend, both within a day and a half of Larman's.

While prosecutors decline to identify a motive, some connected with the case have theorized that Chander Matta, 21, snapped after breaking up with a longtime girlfriend. Sources said the prostitutes all resembled the girlfriend.

A credit card slip bearing Jagjit Matta's name was found in a plastic bag wrapped around the neck of Jodie Marie Phillips, whose body was found behind an office complex in Alexandria.

Sources said police found articles of clothing in the Matta home that matched descriptions of garments missing from the dead prostitutes. Chander Matta also made statements to police that investigators have interpreted as confessions.

Jagjit Matta, 49, said he and his wife were at church when police arrived at their South Arlington house around 11 a.m. last Sunday to question their son about Larman's death.

The family, which moved to America from India 17 years ago, was away on a Sikh religious retreat the weekend the women were killed, leaving about 7 a.m. Friday and not returning to Arlington until late Monday. Chander Matta remained at home to work his evening job as a ticket agent for USAir.

On the day his son was arrested, police were already in the home and had questioned his son by the time Jagjit Matta and his wife came home from religious services about 2 p.m.

"They said they found my credit card receipt near the body in a plastic bag," he said. "Did I buy anything at Fantles on March 15, for about seven or eight dollars?"

Matta said that police did not have a search warrant at the time they entered, but that one was brought while they waited.

"You keep a lot of plastic bags here; what do you keep so many for?" Matta said he was asked, as police collected evidence from throughout the house. "Do you keep any twine around?"

Each of the women was killed by asphyxiation. Plastic bags were found on their heads, and their hands had been bound with cord.

Repeatedly, Matta said, he and his son requested lawyers but were told by police that they did not need one, because no one had been charged. The family was taken to the Arlington County Court House.

"They took Bobby in one car and put us in another car," Matta said, referring to Chander by the nickname that school friends use. "When we reached the Arlington Court House, we didn't see him anymore."

Each member of the Matta family was taken to a separate room, Matta said. He said that his son volunteered to take a polygraph test, and that one was administered to the son.

Unbeknownst to the family, investigators took Chander Matta away to be interviewed by Alexandria police. Hours passed between the time Jagjit Matta and his son were separated and their reunion at the Alexandria station.

"He was sitting in a very small room," Matta said. "When I saw him, he burst into tears. He said, 'I don't know what they did to me; they put me under so much stress.' He was very shaken up."

Matta said he was finally able to contact a lawyer the next day, after his son's arrest. Police officials could not be reached yesterday to comment on Jagjit Matta's account.

These days the family travels in the company of friends and relations, who lend the family moral support. Jagjit Matta has a brother and two sisters who reside in the Washington area. He said other members of the Indian community in the area have also rallied around them since the arrest.

"They visit me, they keep calling me. They said they don't believe that such a thing has happened. Anything you need, just let us know," said Matta, who has retired as an electronics manufacturing supervisor because of a back injury. "Everybody says, 'God be with you.' "

The father's portrait of his son was consistent with that painted by friends and teachers: dutiful, respectful, obedient. He boasted about his son's ROTC medals. "He played basketball, football. He was quiet, gentle, just a normal person."

During only one period of his son's life, he said, from September 1988 to May 1989 -- when his son attended a military college in Vermont -- did Chander Matta seem visibly altered.

"After that one year . . . we brought him back, because he was losing a lot of weight," Jagjit Matta said. He probably couldn't take the pressure there."

Chander Matta then worked at the Washington Navy Yard and at an Arlington video store, before enrolling in Northern Virginia Community College last fall. The studies were broken off when the son encountered academic and financial difficulties.

Despite failing grades at college, Chander Matta wanted to continue his studies of business administration this fall, his father said, possibly at George Mason University or at Old Dominion.

"We talked about {his poor grades}," Jagjit Matta said. "He said he would improve next semester. He said, "Dad, I'm trying."

"It might be that college studies are so much harder and so much more pressure," he said, explaining his son's academic difficulties. "He was ambitious. He wanted to look for a job on Wall Street."

Jagjit Matta has seen his son twice since he was arrested, and said he planned to visit himlast night, after an interview in his lawyer's Washington office. The visits are used to impart consolation to Chander Matta, who faces life in prison without parole if convicted.

"We are trying to give him encouragement to hold on there," Jagjit Matta said. "I told him we are all behind him . . . . That we support him and we love him all the way."