Former high-ranking CIA official John A. Paisley, whose body was found Oct, 1 in the Cheasapeake Bay, probably committed suicide although investigators are still calling it an "undetermined death."

That is the option at Maryland State Police to have investigated Paisley's mysterious disappearance and death by gunshot. Paisley set sail alone in his 31-foot sloop, the Brillig, Sept. 24. Although the boat was found aground the next day, Paisley's bloated body, weighted down by two diving belts weighing a total of 38 pounds, was not recovered for a week.

"We have been unable to uncover any indication whatsoever of foul play involved with the death of Mr. Paisley," State Police Superintendent Thomas S. Smith said yesterday at a press conference at his headquarters in Pikesville.

Because of the bizarre circumstances surrounding Paisley's death, a team of seven state police investigators was assigned to the case.

Information uncovered by that team points to suicide, Smith said, but "we are still classifying this case as an undetermined death."

A spokesman for the Senate Intelligence Committee, which began an independent inquiry into reported links between Paisley's death and missing CIA documents, said that investigation is continuing and results will be made public within two weeks.

Cap. Paul Rappaport, head of the state police investigation into Paisley's death, joined Smith, two FBI agents and a representative from the state medical examiner's office at yesterday's press conference in an unusual hour-long briefing.

Rappaport cited several factors to support the suicide theory. Although Paisley's estranged wife Maryann has been quoted as saying he was "infine spirits" at the time of his death, Paisley had talked about suicide two years ago, according to Rappaport. "Associates have told us he had been depressed but was coming out of it," Rappaport said. "Sometimes that's the most critical time."

Paisley's psychiatrist, Dr. Jack Baruch, told a reporter last week that the 55-year-old retired CIA official had given "absolutely no clues" that he was contemplating suicide but may ave had "feelings of loss and abandonment" because of recent developments in his personal life.

Rappaport also said Paisley once told an associate, "if he should die, he wanted to die in the water. . . .. He said he wanted to be buried at sea."

The bullet that killed Paisley, striking him above and behind the left ear, was fired from a 9 mm automatic pistol, the type of gun Paisley was known to keep aboard his sailboat. Although Paisley reportedly told a friend he wanted to sell the gun this summer, Rappaport said yesterday the gun was seen on the boat one week prior to Paisley's disapperance. The weapon has not been found, police said.

Although no bloodstains were found on Paisley's boat, police theorize he could have shot himself while leaning over the water or hanging from the boat's side.

FBI agent John Kilty said no traces of gunpowder were found on Paisley's hands. "We cannot tell if the man fired the gun," Kilty said, adding that any chemical residue would be washed off in the water.

Initially, the presence of two weighted diving belts on Paisley's body was a mystery, but state police previously reported their discovery that Paisley had bought a second belt at a Northwest Washington diving shop on Sept. 8. Paisley was said to be an expert skindiver, but skindivers ordinarily would have no use for more than one belt.

Smith also said police are looing into a similar death, that of Yale University Professor Richard Wolfgang, who was found shot to death, his body weighted down with rocks, in Long Island Sound in June 1971. Wofgang was a chemist who did research with nuclear reactors. His death was ruled a suicide.

Police said they had requested Paisley's CIA personnel file. Paisley retired as director of the CIA's Office of Strategic Research in 1974, but had been retained as a consultant. At the time of his death, Paisley was also earning $36,000 a year as an executive assistant at the accounting firm of Coopers & Lybrand.

Rappaport said police are also checking into Paisley's life insurance. According to the family attorney Terence O'Grady, Paisley was covered by a government insurance policy, and suicide would not affect payment of benefits.

Although CIA documents pertaining to Paisley's most recent project were found on the boat and in his apartment at 1500 Massachusetts Ave. NW., CIA spokesmen have denied that Paisley was in any way involved with a breach in the security in the agency's so-called KH-11 satellite surveillance system. A report in a Wilmington, Del., newspaper had linked Paisley to the thefe of documents related to that system.

State police said yesterday they have removed five of the seven investigators from the case, but will continue their inquiry into Paisley's death.