After interrogating him around the clock, Prince George's County police late last night charged an estranged husband in the slaying of his wife, who apparently was killed while she was out for a morning jog.

Keith Anthony Longtin, 44, of Crofton, was charged with first-degree murder in the death Monday of Donna A. Zinetti, 36, of Laurel.

Julie Valdes, a police spokeswoman, said the "information obtained from [Longtin] resulted in him being charged with the murder." She would not elaborate.

Police began to question Longtin at police headquarters in Palmer Park early Tuesday afternoon. Zinetti's body was found in a patch of woods about 2 p.m. Monday near her home in the 13100 block of Larchdale Road.

Police had said that detectives finished their interview Tuesday night and that Longtin had left. But they acknowledged yesterday that Longtin had never left the police station and remained there throughout Tuesday night and all day yesterday.

Hours before he was charged, police said Longtin was still not a suspect.

"I understand he's here of his own free will," said Cpl. Irene Huskens, a police spokeswoman.

Longtin was taken to police headquarters for questioning shortly after he arrived at the crime scene Tuesday in a battered late-model Buick and began talking to reporters about his missing wife. His eyes moist with tears, he said he had been separated from Zinetti and had last seen her at church on Sunday, when they had "a disagreement."

He said he filed a missing person report at the police department's district station in Beltsville about 3 a.m. Tuesday after Zinetti didn't return his phone calls or pages. Police said yesterday that they have no evidence that such a report was filed.

Police said Zinetti's body was discovered at the crest of a ravine in the Larchdale Woods apartment complex by a neighbor who was walking her dog. Investigators said Zinetti had been stabbed repeatedly, but they said the official cause of death is pending.

Zinetti was last seen about 6:30 a.m. Monday by several neighbors as she went out for a run. Police said she was wearing her jogging clothes when she was found.

Friends of Longtin and Zinetti said the couple married about a year and a half ago after dating for two weeks. Zinetti worked at home as a medical transcriptionist, and Longtin was employed at an auto parts store in Rockville.

Records show that Longtin has been arrested four times on assault and battery charges in Prince George's and Montgomery counties since 1996. In each case, prosecutors later dropped the charges.

Zinetti grew up in Massachusetts and moved to Prince George's in the early 1990s to live with her boyfriend, Gary S. Gregorio, of Bowie.

In November 1996, Zinetti filed a criminal complaint against Gregorio, alleging that he assaulted her on three occasions, ripping her clothes off her back and leaving her with a black eye. Gregorio pleaded guilty in April 1997 and was given a one-year suspended sentence and two years' supervised probation.

Gregorio did not return telephone calls yesterday.

After Gregorio's conviction, Zinetti wrote to Prince George's Circuit Court Judge William D. Missouri to complain that she had been treated shabbily by prosecutors and court personnel. She said that she was ignored throughout the proceedings and that no one bothered to inform her that her boyfriend had pleaded guilty.

She told the judge she had lost her job and her health insurance and had been forced to move three times to find an affordable apartment. The abuse was bad enough, she said, but her experience with the court system had left her even more bruised.

"I am disgusted and hurt! This system does not work for the victim!" she wrote in the letter, dated June 26, 1997, and filed with the court. "I have been living day to day, trying to get my life back together. This has thrown me into a deep depression for which I'm presently being treated. My financial, as well as my mental status, are at their very worst."

Staff writers Steven Gray and Allan Lengel and researcher Bobbye Pratt contributed to this report.