SAN DIEGO -- The original lead investigator in the Stephanie Crowe murder case testified Thursday he may have been "wrong" when he told a grand jury that blood was found on a knife thought to be the murder weapon.

Retired Escondido police Detective Ralph Claytor, (pictured, right), a defense witness, was called to the stand for a second straight day in the trial of Richard Tuite, a transient charged two years ago with the 12-year-old's death.

The former detective said he testified in May 1998 before a grand jury convened to secure a murder indictment against Stephanie's older brother Michael and friends Josh Treadway and Aaron Houser.

Under cross-examination from Prosecutor David Druliner, Claytor said he tried to tell the truth when he told the grand jury blood was found on a "Best Defense" knife investigators found during a search of Treadway's family home.

Claytor said his knowledge at the time was that there was a positive presumptive test for blood on the knife, but there wasn't enough to get any DNA results.

"Were you wrong?" Druliner asked.

"It's possible I was wrong," Claytor said.

He admitted lying to Treadway during a 10-hour interrogation about the Best Defense knife in an attempt to get the 15-year-old to incriminate himself or provide more information to help the murder investigation.

Michael Crowe, Treadway and Houser originally were charged with stabbing Stephanie to death.

Attorneys for Tuite told the jury Escondido police had it right when they fingered the three friends as the killers.

Michael Crowe hated his sister and recruited his friends to help him carry out the murder, Tuite's attorneys theorize.

Defense attorneys also contend Michael Crowe let Houser into the Crowe residence the night of Jan. 20, 1998, and the two proceeded to Stephanie's room and killed her.

Murder charges against the boys were dropped in 1999 after the victim's blood was found on a sweatshirt Tuite was wearing the night of the murder. Her blood also was found later on Tuite's white T-shirt.

Tuite, 34, was charged after the case was handed over to the San Diego County Sheriff's Department and the state Attorney's General Office.

The defense contends the blood evidence was contaminated.

Prosecutors contend Tuite -- a diagnosed schizophrenic -- was in the area of the Crowe residence the night of the murder, asking for a friend named "Tracy."

Evidence also has been presented that the defendant liked to carry a knife.