A cop killer whose 2011 parole announcement ignited fierce criticism from politicians and police officers is back in prison.

Tim Eling hasn’t been convicted of a new crime, but he violated the terms of his release by testing positive for methamphetamine during a routine drug test, said Sarah Fitzgerald, a spokeswoman for the Department of Corrections.

In 1982, Eling and accomplices dressed in ski masks and robbed Mounds Park Pharmacy. Richard Walton, an off-duty Oakdale police officer, was moonlighting as a security guard and walked into a blaze of gunfire after an employee hit the store’s alarm. Walton managed to squeeze off a round, hitting Eling in the leg, before Eling shot him in the head. He died 12 hours later.

Eling was convicted of first-degree murder and sentenced to life in prison. But this was still a decade before Minnesota would pass a law prohibiting parole for someone found guilty of killing a police officer.

Still, the release of a cop killer is extremely rare in Minnesota, and it caught many by surprise. Legislative and law enforcement leaders demanded an explanation from DOC Commissioner Tom Roy, who made the decision to parole Eling after a review hearing.

At the time, Roy attributed his decision to Eling’s good behavior in the latter half of his sentence, which included mentoring younger offenders in drug rehabilitation.

“His parole was granted because he met the requirements laid out in the law that permit it,” Roy said in a statement to reporters in 2011. “If he cannot stay on that path he will not be allowed to remain in society.”

Asked for comment this week, Roy called it “a sad example of the power of addiction — that even when given this opportunity, some will succumb to using substances again.”

“The return to prison is the consequence for this failure,” Roy said in an e-mailed statement.

Eling wasn’t released until 2015, after serving a consecutive sentence for smuggling drugs into prison in 1996. He was reincarcerated in October 2016 — about a year after his release — and currently resides in Minnesota Correctional Facility-Lino Lakes.

In a 2011 interview with the Star Tribune, Eling said he understood the visceral reaction toward his release. “I’d probably feel the same way,” he said. “The record speaks for itself. I have not been a good person in this life.”

He also said he’d been diagnosed with cancer, and it was unclear if he would live to see his freedom.

Amy Koch, who, as Senate majority leader, wrote a letter to Gov. Mark Dayton protesting Eling’s release in 2011, said she didn’t know Eling had returned to prison until informed by the Star Tribune.

“I just think we were right in 2011,” Koch said. “What he did is something that he has to pay the price for.”

Regarding his recent violation, she said, “We’ll see what comes of this.”

Andy Skoogman, executive director for the state’s police chief association, said he does believe rehabilitation is possible for criminal offenders. Yet in the case of Eling, he said, “I’m neither surprised nor saddened.”

Eling will go back in front of a review panel in 2018.