DENVER — When a revered former Colorado sheriff pleaded guilty to plying young men with methamphetamine in exchange for sexual favors two years ago, his colleagues were stunned.

But when a judge spared him prison time, ordering probation instead, some held hope that Patrick Sullivan, once named the nation’s top sheriff, would be able to redeem his tarnished image.

Instead, the former Arapahoe County sheriff again faces prison when he is sentenced Thursday for violating his probation for at least the third time, repeatedly testing positive for drugs and alcohol since his felony conviction.

“I’m not shocked anymore,” said former Boulder County Sheriff George Epp. “What it tells me is a switch flipped somehow and it hasn’t flipped back.”

The hearing is expected to draw supporters, but also some still angered by a sentence they saw as too light.

Sullivan’s attorney did not return calls seeking comment Wednesday. A number listed for Sullivan was disconnected.

Before his arrest in December 2011, Sullivan, 71, was known as an anti-drug crusader, a lawman with a record so distinguished the county named its jail after him. The National Sheriffs’ Association tapped him as its “top sheriff” in 2001, and he continued to command respect even after he resigned the following year to oversee security for a school district.

But a darker picture of Sullivan emerged. A 911 caller asked police to remove from his home an “old man” who was trying to get three recovering addicts back on drugs. Authorities later learned the old man was Sullivan, and he was dealing meth to men in exchange for sex. Sullivan would develop relationships with vulnerable young men, help them find jobs and get out of jail, and then provide them the drug.

“I was just thunderstruck,” Epp said. “It was a complete 180-degree turn from the person I knew.”

Police charged him with a string of crimes, but he pleaded guilty only to possession of methamphetamine and solicitation of a prostitute. A judge sentenced him to 30 days in jail and 24 months’ probation. Sullivan’s first violation came four months later and carried no punishment. His probation officer said he had been “manipulative” and dishonest in missing drug therapy and drug tests and had tested positive for alcohol.

In March, a judge extended his probation by three months for failing a urine test. And in May, court documents revealed the disgraced former sheriff had repeatedly failed drug and alcohol tests that showed he had again used methamphetamine. He confessed only to leaving the state without permission, but a judge ordered further investigation on the drug tests.

“This is just a very, very sad situation,” said Colorado’s U.S. marshal, John Kammerzell, who knew Sullivan for 36 years.

In 1989, Sullivan was hailed as a hero. During a gunman’s rampage, he rescued two deputies after crashing his truck through a fence and protected them while they were loaded into the vehicle. In the day to day, he was a tough-as-nails lawman who knew how to get what he wanted.

“There were times when he seemed to be over the top, trying so hard to compete, to be ahead of everybody,” Epp said. “We used to kid other sheriffs that wherever there were television cameras, he’d smell them out and get to them.”

He would often show up before county commissioners on Friday afternoons with packets of information promoting his causes, which usually included more money for equipment and training, said former Commissioner John Brackney.

“I wish him success in overcoming the difficulties that he’s clearly had,” Brackney said.

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