Original Article Oct 28, 4:30 AM EDT Judge asked to revoke probation of retired police officer TUCSON, Ariz. (AP) -- A judge has been asked to revoke the probation of a retired Tucson police officer arrested two years ago for using the Internet to set up a sexual encounter with a person he thought was an underage girl. Charles Kenneth Walter, a 21-year police veteran, was arrested in December 2003 after showing up for the meeting. The girl turned out to be an undercover officer, and Walter was charged with luring a minor for sexual exploitation and computer tampering. Walter, who retired after his arrest, pleaded guilty to computer tampering with sexual motives and was sentenced to three years' probation. He was also ordered to undergo counseling and register as a sex offender. On Thursday, the Probation Department asked Pima County Superior Court Judge Howard Fell to revoke Walter's probation for several reasons. Walter, 50, is being held without bail in the county jail pending a hearing to discuss the allegations.