WESTMINSTER, Colo. -- The clues are few: bullet holes, blood and a piece of scalp.

It's been six years since Paul Skiba, his 9-year-old daughter Sarah Arielle Skiba, and Lorenzo Chivers mysteriously disappeared in Colorado. Clues after their disappearance led police to theorize that the three were killed.

Wednesday a, $8,500 reward was announced for information leading to the identification and prosecution of those responsible for the crime. The reward was offered by Families of Homicide Victims and Missing Persons and Crime Stoppers.

The three were last seen on Feb. 7, 1999, when Paul Skiba and Lorenzo Chivers went to a moving job in Morrison, Colo., and Paul's daughter tagged along. When they weren't heard from for a week, Paul's ex-wife and a friend went to the moving company lot in Westminster and found the moving truck parked with bullet holes, blood and a bloody piece of scalp.

A DNA test revealed that blood found in a moving van belonged to Paul and Sarah Skiba, the scalp to Paul. Chivers, who has also not been seen since, was the father of a son and daughter the same age as Sarah.

Investigators learned that the truck had left the lot at about 9 p.m. and was returned about midnight. Police theorize the three were killed at the lot and the truck was used to dispose of their bodies. It was then driven back to the lot and parked. No trace of the three has ever been found.

Families of Homicide Victims and Missing Persons unveiled a large billboard that was erected near the crime scene in hopes it will spur someone to come forward about what happened to the trio. It shows pictures of the three and asks, "Who killed us?"

"Anything's possible if people are willing to talk," said Tim Read of the Westminster Police Department.