Los Angeles (CNN) -- The recent discovery of a severed head, two hands and two feet in the Hollywood hills is near the home of actor Brad Pitt, and authorities have interviewed his bodyguard for possible leads, police said Thursday.
"It's standard procedure for us to have our detectives canvass the neighborhood," Los Angeles Police Cmdr. Andrew Smith said. The bodyguard saw nothing unusual, he said.
In an unusual coincidence, Pitt starred in the film "Seven," in which he plays a detective and a severed head is found a box.
Meanwhile, the dog walker whose canine discovered the head in a park near the Hollywood sign said she at first thought the head was a movie prop.
"Our assumption was that there was always people filming up there, and it was a prop," Lauren Kornberg told HLN. "We walked down the ravine and got closer and realized it was a freshly severed human head."
In what police described as their biggest search in recent memory, 120 investigators scoured a seven-acre parcel of a park looking for clues in the dismemberment, which authorities believe occurred elsewhere, Smith said.
"We don't believe the murder occurred up here in the hills," Smith told reporters. "Right now, there is somebody who committed murder somewhere out there."
As of late Thursday morning, police hadn't discovered any more remains or significant clues, Smith said.
At least 30 Los Angeles police officers, a dozen coroner's investigators, helicopters, all-terrain vehicles, a SWAT team trained in climbing skills and mounted officers were searching a section of Bronson Canyon, next to Griffith Park, Smith said.
The coroner's cadaver dog, who Smith said became exhausted at times Wednesday, was back on the trail after sunrise Thursday, sniffing for more remains of the victim. But authorities still haven't located the torso.
"We're going to leave no stone unturned," Smith said.
The head is that of a man between 40 and 60 years old, with salt-and-pepper-colored hair, Los Angeles County Deputy Chief Coroner Ed Winter said. Investigators "have every reason to believe" the hands, feet and head belonged to the same person, Smith said.
Fingerprints taken from the severed hands could help identify the man, police said.
"That's what we're hoping," Smith said.
Investigators also will use dental records and DNA in trying to identify the victim, but they are hoping the fingerprints could more readily provide an identification.
Authorities plan to conclude their three-day hillside search Thursday afternoon and reopen the park to the public Friday, Smith said.
"We ask people to be cautious. Hike with friends. Don't go off alone," the commander advised.
Searchers using the coroner's cadaver dog located the two hands and two feet scattered across seven acres of brushy and steep terrain, police said.
Authorities believe the human remains were placed in one spot and then were spread by wild animals, Smith said.
"With the wildlife we have here with the coyotes and whatnot, if a body part is left up there, it's not long before it's disturbed by the animals," he said.
The body parts were hidden until the animals found them, Smith said.
"You could say it was a determined effort to hide them," Smith said of the body parts, declining to elaborate. "There was no intent that these were something that the public would find."
Wednesday's search located first one hand, about 50 yards from where the head was found. Another hand and then two feet were found just before waning daylight forced an end to that day's search, police Officer Cleon Joseph said.
The person who placed the severed appendages in the Hollywood hills had to go out of his way, walking to an off-the-beaten-path location to leave the limbs, Smith said.
"Had it not been for the dog walker, we may not have found" the remains, Smith said.
The real-life Hollywood mystery began Tuesday afternoon when two people noticed their dogs dragging a plastic grocery bag from a bush near a dirt trail, police said. The women were shocked when they realized a severed head was inside.
In an interview with HLN, Kornberg, the dog walker, said she was walking eight dogs when one of them, a golden retriever named Ollie, ran away from her. Kornberg was joined by her mother, who was walking her own dog.
"We were wandering the trail and the dogs are sniffing around, and he (Ollie) pulled away from me and made a beeline for some brush. He was barking," Kornberg said.
"A few minutes later, he had something in his mouth, which he immediately dropped," Kornberg said.
The object rolled down the ravine, Kornberg said.
Kornberg and her mother discovered it was a human head belonging to what she described as a white man.
"We were pretty much gasping, saying, 'Oh, my God!' I was shaking. It felt like a script," Kornberg said. "It still doesn't feel real."
The secluded trails, adjacent to Griffith Park, are a favorite place for residents, including many celebrities, to walk their dogs or hike.
The coroner's office is examining whether the man was dead when the dismemberment occurred, and what kind of instrument may have been used to remove the head and limbs, Smith said.
Police don't have a theory on what happened.
"Right now, we're keeping an open mind ... on why this poor person was dismembered and deposited up there," Smith said.
Detectives estimated the man had been dead since Sunday.
Police are also checking recent missing-person reports for leads, Winter said.
CNN's Chuck Conder and Rosalina Nieves and HLN's Selin Darkalstanian contributed to this report.