State and federal authorities are asking for the public's help in finding a violent sex offender who escaped from a Denver halfway house.

The search for Eric E. Hartwell was focused on the Denver area on Monday.
He's been at large since Friday, when he cut off his ankle bracelet.
Hartwell - a 6-foot-2 man with blonde hair, blue eyes and a tattoo on his right hand -was sentenced to three years in prison in 2011 in Clear Creek County west of Denver for failing to register as a sex offender.
A spokesman for the U.S. Marshal's Service, Charlie Ahmad, says a substantial reward is being offered for help finding him. He says Hartwell has tried to resist capture before and is considered extremely violent.