On any given day, some 15,000 criminals mingle with Utahns in stores, schools and neighborhoods.

They are petty thieves and sex offenders. Gangbangers and drug addicts. Scam artists and killers.

About 11,000 are on probation, meaning a judge imposed supervision by Utah Adult Probation and Parole. Another 4,000 are on parole, meaning they did time in a prison cell at Point of the Mountain or Gunnison.

So who watches these criminal offenders?

They are supervised by 450 parole and probation officers tasked with the delicate dual role of police officer and social worker — and they go largely unnoticed until something bad happens, as when parolee James William Tolbert killed a Murray woman in October.

"We deal with a population that society would really rather not think about," said Tony Brown, an AP&P supervisor who shepherds a team of agents supervising hundreds of offenders.

Prison. Time served. Justice. Rehabilitation. The public wants inmates to do their time, get out and be good.

But who guides someone like Monique Knudsen, 30, whose father was a drug addict, a criminal and a recruiter for the Sundowners motorcycle gang? Who shows her how to stay off drugs and work when her mother was an addict and she was raised in a life of crime?

The mother of four has spent four of the past eight years in prison. She essentially never had a job until hired on the prison's work crew picking up trash. She's been addicted to meth on and off for 13 years and has been charged with several drug-related crimes over the years.

"I wish I had a decent role model," she said this month from prison. Set to be paroled in January, Knudsen reluctantly admits the need for supervision. "I can't always be strong."

'Dirty little secret'

Parole agents are sworn police officers. They chase down parole violators, make arrests and enforce rules established by the Board of Pardons and Parole. They also make endless phone calls and arrangements, working out details of housing, employment, schooling. They watch people urinate for drug tests.

"It's one hat with two bills," said Robyn Williams, deputy director of operations for Utah's Department of Corrections.

The agents can be an offender's best friend or worst nightmare. An agent's time can be spent catching a parolee doing things wrong or working at becoming a respected member of society, Williams said.

"Ultimately, the offender gets to make that choice."

Some choose wisely. Many don't.

An estimated half of all parolees will be back in prison within a year of their releases. About 65 percent will return within three years. Some say privately the "dirty little secret" in the corrections department is that parole violators make up about half of the prison's annual population growth.