Fairfax County school officials said yesterday they were unaware that a teacher under investigation for alleged sexual abuse at the time of his suicide last week had been the subject of a similar inquiry by county police in 1984.

The disclosure, first reported yesterday by the Journal newspapers, is another indication of the troubles county school officials have had dealing with complaints about sexual abuses involving personnel in the county schools.

Last year, school officials ordered changes in how they handle police complaints about school employes after they discovered that a school psychologist arrested on sex charges previously had been investigated by Prince William County authorities on similar allegations.

In the latest case, police in Arlington said they were investigating an allegation that Fairfax teacher Richard C. Jarman, 50, had sexually abused a seventh grader at his home on June 7. Police said the student attended Key Intermediate School in Springfield, where Jarman taught history.

Jarman, who shot himself last Thursday while in a pew at the Clarendon Presbyterian Church, also was under investigation by the Fairfax school system on a complaint about his friendships with children.

No formal charges had been filed in either Fairfax or Arlington.

Top school system officials said yesterday they were unaware that Fairfax police investigated Jarman in the spring of 1984, when he was teaching at Whittier Intermediate School in Falls Church. No evidence of wrongdoing was found in that inquiry, police spokesman Warren Carmichael said.

Carmichael said police investigators did not notify the school system's top personnel officials of their inquiry, but did speak with "someone in a responsible position" about it. "We're satisfied that there was communication with the school system," he said.

Gary W. Miller, who was Whittier principal at the time, said, however, he was unaware of the police investigation and school spokeswoman Dolores Bohen said higher-level school system administrators, including personnel chief Warren Eisenhower, were not notified.

Jarman had been informed of the school system investigation a week before his death and was told no conclusion had been reached, Bohen said.

She said Jarman's principal at Key had warned him last fall not to socialize with students after hearing that he had invited a child to a Redskins game. She described him as a well-liked teacher who had taught in Fairfax County for 27 years. He began teaching at Key Intermediate in the fall of 1984, a few months after Whittier was closed.