Tests showed that a series of suspicious stains in Scott Peterson's (search) pickup truck were not blood, and there was no incriminating evidence in a tool box in the vehicle, a detective testified Monday at Peterson's murder trial.

Police Detective Henry "Dodge" Hendee returned to the witness stand as defense attorney Mark Geragos (search) resumed his attack on the investigation into the deaths of Peterson's wife, Laci, and unborn son. He pointed out for jurors that eight stains found in Peterson's truck — blotches in places including the steering wheel and door that police suspected were blood — all tested negative.

Hendee could not say whether another stain, found on the truck's carpet, tested positive.

Geragos also asked Hendee about a hair found inside the large tool box in the bed of Peterson's truck, pointing out that tests indicated it came from an officer processing the crime scene.

"At the time I thought it could possibly be Laci's," Hendee said.

Prosecutors allege Peterson used the tool box to conceal Laci Peterson's body while taking it from the couple's Modesto home to San Francisco Bay.

Hendee acknowledged Monday that no incriminating evidence was found on the tool box.

"Is it fair to say that there was no tissue-like debris collected from anywhere on the tool box?" Geragos asked.

"That is correct," Hendee replied.

Geragos has been portraying the prosecution case as an exhaustive search for hard evidence that turned up nothing incriminating. In a barrage of sarcastic questions last week, he forced Hendee to acknowledge at nearly every turn that searches of San Francisco Bay yielded nothing to link Peterson to the killing of his pregnant wife.

Prosecutors allege Peterson murdered his wife in their Modesto home on or around Dec. 24, 2002, then dumped the body in the bay.

Peterson acknowledges being on the bay that Christmas Eve day, but said he went fishing alone and found his home empty when he returned. Geragos asserts that someone else abducted and killed Laci Peterson, then framed her husband.

The remains of Laci Peterson and the couple's male fetus washed ashore just two miles from where Peterson claims he was fishing.

Geragos has accused a detective of lying on the witness stand and is seeking a dismissal of the charges or a mistrial. The judge set a July 29 hearing on the matter.