Authorities probing the slaying of a Baltimore federal prosecutor are expected to decide the future course of the investigation today and could announce that it will be pursued as a local murder case in the Pennsylvania county where his body was found, not as a federal crime.

Investigators gathered information over the weekend on Jonathan P. Luna's private life that could help explain his death. One law enforcement source said yesterday that Luna, 38, had suffered severe beating injuries in his genital area before he was killed, suggesting a "highly personal" motive behind the crime.

Federal agents questioned Luna's family and friends about recent trips he might have taken to Pennsylvania, his personal life as well as his finances, according to family members and law enforcement sources. One source said agents were investigating whether Luna's credit card was used in the Philadelphia area the night he disappeared.

Authorities also were examining messages posted by someone using the name Jonathan Luna on Internet dating sites. The author of the messages, from April 1997, described himself as a discreet 31-year-old married, professional black male seeking a white female sexual partner; but the authenticity of the postings could not be verified yesterday.

'Perfect couple'

The slain prosecutor's father, Paul D. Luna, 83, said yesterday that FBI agents had told him that they thought his son's death was not connected to his work. Among other things, agents were asking whether Luna had a girlfriend, a notion rejected by family members who said Luna and his wife, Angela, were the "perfect couple" and doted on their two young sons.

A law enforcement official told The Sun on Friday that authorities suspected Luna's death was the result of a personal relationship that turned violent and was not a random act of violence or in retaliation for his job. If Luna left Maryland willingly and was not targeted because of his job, it is unlikely that his death could be prosecuted as a federal kidnapping case or the murder of a federal official.

Officials could announce today that the case is expected to be prosecuted by the local district attorney in Pennsylvania, who was scheduled to meet with Luna's boss, Maryland U.S. Attorney Thomas M. DiBiagio.

DiBiagio vowed last week to find Luna's killer, but his office has declined to make further comment on the investigation. The Lancaster County prosecutor, Donald R. Totaro, said he would not comment until after today's meeting in Baltimore.

Luna's body was found shortly before dawn Thursday, stabbed 36 times and left face down in a creek in rural Brecknock Township, Pa. A source close to the investigation said yesterday that Luna's battered body was positioned directly in front of his still-idling Honda Accord, suggesting that his attacker might have considered running over the body before retreating.

The condition of Luna's body and the apparent zeal of killing prompted investigators to examine whether the killing was the result of a personal conflict. Two law enforcement sources said yesterday that Luna's genital area was severely wounded, with one source describing the injuries as consistent with beating and bruising.

Retracing steps

The mystery of what happened to Luna was complicated in part by the relatively short time he was missing. Luna was concluding a drug conspiracy trial in U.S. District Court in Baltimore on Wednesday, and he had returned to the courthouse that night after telling a defense lawyer that he planned to complete the paperwork for an expected plea deal the next morning.

Luna left the courthouse after 11:30 p.m. Wednesday, and his body was discovered about six hours later and about 70 miles northeast of downtown Baltimore. Law enforcement sources have indicated that officials retracing Luna's steps think that he traveled through Delaware, toward Philadelphia, and made a series of ATM withdrawals along the route.

Brecknock Township, where Luna's body was found, is about 80 miles west of Philadelphia.

FBI agents have questioned Luna's family about recent trips he took to Pennsylvania. One was as recent as the Friday after Thanksgiving, when Paul D. Luna has said his son had to cancel a planned trip to New York City to travel to Pennsylvania for work.

The government's central witness in Luna's drug conspiracy case that began the next Monday was a Baltimore man named Warren Grace, who was being detained at a facility outside Philadelphia, Maryland Federal Public Defender James Wyda said yesterday.

Grace, who was represented by the federal public defender's office, had met with Luna at the Pennsylvania facility several time in recent months, Wyda said.

Questions remained, though, about what would have drawn Luna to Pennsylvania late on a night when he had work to complete in the case and was expected to be back in the courtroom at 9:30 a.m.

Authorities have not identified any suspects in Luna's killing. But in Pennsylvania, local leaders were confident that the case would be solved.

"You're always concerned with acts of this viciousness," said Paul R. Thibault, chairman of the Lancaster County board of commissioners. "But I would put my money on the police solving this."

Sun staff writer Lynn Anderson contributed to this article.