PARKER, Colo. -- Police have identified a man they say burglarized three homes in December and threatened a homeowner with a knife. They now are asking the public to help them find the man.

A warrant has been issued for the arrest of Gregory Phillip Casias, 46, on charges of robbery, burglary, felony theft, criminal mischief and several other related crimes, police said. Crime Stoppers is offering a reward up to $2,000 for information leading to Casias' arrest.

Casias is accused of burglarizing three homes in Parker and unincorporated Douglas County on Dec. 17. Police have said he used a softball-sized boulder to break into the homes. In one burglary, he confronted a homeowner who was returning from work and threatened to stab man with a knife.

"The gentleman ran out of our master bedroom, down our stairs and met me here in the hall," the homeowner, Tim Campbell, told 7News last week. Campbell began yelling at the intruder, and that's when the man started threatening him.

"He claimed he had a knife and that he would use it," said Campbell. "He said he'd stab me and kill me."

Two of the burglaries were in Parker's Quail Ridge Estates, where homeowners reported jewelry stolen. The third burglary occurred in the Bell Cross Estates subdivision in unincorporated Douglas County.

Anyone with information about Casias is asked to call Crime Stoppers at 720-913-STOP (7867), or the Parker Police Department at 303-841-9800.