Prince William police have been unable to identify a man who was found dead in a creek last week, hampering investigation into the county's 12th homicide this year.

Police said yesterday they believe the man, estimated to be in his early fifties, was brought to the creek near Mace Street just outside Manassas after he was attacked. The man was found dead Sept. 28. Police think he may not be from the area.

Detectives have scoured the woods for clues but have been unable to gather much information about the man, and police are appealing to the public for help in identifying him. Police spokeswoman Sgt. Kim Chinn said yesterday that the investigation has stalled largely because detectives don't know the victim's identity.

"We think there may be a crime scene elsewhere," Chinn said, adding that police have no suspects. "Without identifying the victim, it's hard to establish a motive, and we haven't been able to notify the family."

Two children playing in the woods behind Loch Lomond Baptist Church noticed the man's body about 6 p.m. Police said the man was partially clothed when the body was discovered and that he was wearing Hollander brand underwear with tags that read: "Made in Europe."

An autopsy last week revealed the man died from blunt force trauma to the head, though police have not determined what may have caused the injury. Police said that the injury was not self-inflicted, and detectives are treating the case as a homicide.

The man's fingerprints do not match with any in the state and federal crime databases, and medical examiners are unable to use his dental records to identify him because they don't know his name. Chinn said no recent missing person reports match the man's description, leaving police unsure of whether he lived in the area.

The man's death was the 12th homicide of the year in Prince William County, tying a modern-day record set in 1995. Police have closed or made arrests in nine of the cases; other than last week's homicide, two remain unsolved.

Detectives have released a computer-enhanced image of the man, which was compiled from pictures taken after his death, hoping that someone in the community will recognize him. Police said the man was clean-cut and had a missing tooth, which they believe was not related to injuries sustained in his attack.

Police have asked anyone who recognizes the man or has any information that might lead to his identity to call the Prince William County Police Department's Crime Solvers line, at 703-670-3700.

CAPTION: Children found this man's body in a creek last week.