Pathologists believe they know how two girls buried at a pig farm were slain, but officials will not reveal their findings.
"We're holding that back to protect the integrity of the case," said Salt Lake County sheriff's Capt. Dean Carr, who is overseeing the investigation into the deaths of Tuesday Roberts, 15, and Lisa Martinez, 16.Investigators plan to meet with Salt Lake County Deputy District Attorney Kent Morgan next week about filing charges.
The prime suspect is Roberto Arguelles, 33, who is serving a life sentence. He was on parole when Roberts and Martinez disappeared March 30, 1992. At the time, Arguelles was staying in an adobe house at the pig farm, owned by his step-father.
On Aug. 8, 1992, Arguelles was arrested, but not charged, when he attempted to abduct two 10-year-old girls in West Valley City near Hunter High School, according to a police report. He was linked to the Aug. 1 molestation of an 8-year-old boy and the child's 10-year-old sister and was convicted.
In March 1980, he raped two teenage girls near the pig farm during two separate attacks. He slashed a 14-year-old girl's throat and stabbed her, but drove her to a nearby home.
While in prison, he told investigators where to find the bodies and claimed two other men killed and buried the teens.