Suicide Adds to Mystery Of Corpse Found in Barrel The mystery of a pregnant woman murdered long ago and hidden for decades in a steel drum under a home on Long Island until her mummified remains were found 11 days ago has taken another strange twist. Elkins, 71, the first of five owners of the white split-level home at 67 Forest Drive in Jericho, N.Y., where the body was found, was interrogated by Nassau County homicide investigators on Thursday at his retirement home in a condominium community in Boca Raton, Fla. Later that evening, he was found by a son in the garage of a friend's house in Boca Raton, the victim of an apparently self-inflicted shotgun blast to the head. ''We are aware that the man did commit suicide in Florida,'' Officer Doreen McGuinness, a Nassau County police spokeswoman, said yesterday. Elkins seemed to suggest, investigators said they were no closer to unraveling a tangled case whose grim discoveries, tantalizing clues and twisting plot might have been drawn from one of Raymond Chandler's Philip Marlowe mysteries. He insisted that Ronald Cohen, the seller, take it away. They called the police, who removed the body of a woman, her full-term fetus, her apparel and other items, all remarkably well preserved, apparently because the drum had been airtight. Around the neck was a religious scapular and a locket with the words, ''Patrice, Love Uncle Phil.'' A wedding band on the left hand bore an inscription ''M.H.R. An autopsy found that the woman, who was 25 to 30 years old at the time of her death, had been killed by blunt force head trauma, and estimated that she had been dead 25 to 30 years. Investigators learned that the house had been built in 1957 and had had only five owners: Mr. But detectives concluded that the murder must have taken place during a nine-year period between March 1963, when the drum was manufactured in Linden, N.J., as a container for paint and plastic pigments, and October 1972, when it was first reported seen at the house in Jericho. Elkins acknowledged that he had bought the house new in 1957, and had lived in it for 15 years before selling and moving to Florida in 1972. He said that, aside from gardeners, landscapers and maids, he could think of no one who had had access to the property. He was one of a number of people who had not been removed from a list of suspects. Elkins dead in the garage of a friend's home nearby and called the authorities. The Palm Beach County Sheriff's Department reported no signs that the death was anything other than a suicide. Elkins in Florida and on Long Island recalled him as outgoing and friendly, and said it was hard to imagine that he could have ever killed anyone. ''He seemed like a very sociable fellow,'' Frank Lonano, a neighbor in Boca Raton, said of Mr. ''They seemed like such a lovely family,'' she said of the former owners.