Authorities are conducting forensic tests on a 10-inch knife reportedly found at the home where convicted murderer Scott Peterson (search ) lived with his now-dead wife, but questions remain about whether it had been planted there recently.

"You could tell there had been liquid on the blade" and a "red stain on the handle," said Gerry Roberts, the man who recently bought the home.

Roberts said two of his friends found the knife last week inside a cabinet near the swimming pool in the backyard. But investigators said the discovery came just days after a tabloid ran an article containing rumors that Laci Peterson's (search ) throat had been slit.

Modesto (search) police spokesman Rick Applegate said investigators saw "no obvious signs of blood or tissue on the knife."

"It is somewhat believed that this knife was put, planted or placed there recently by a person or persons unknown," Applegate said. "There is nothing to make us believe the knife was used in the crime."

Scott Peterson was sentenced to death in December for murdering Laci Peterson and her fetus.

Roberts, a Modesto real estate agent, paid $390,000 for the couple's three-bedroom, two-bath house, $10,000 more than the asking price.