(CNN) A Catholic archdiocese with a landmark legal legacy in child sexual abuse now faces criminal complaints in its handling of them.

In 1983, attorney Jeff Anderson filed a civil case of priest sexual abuse of minors against a U.S. archdiocese in Saint Paul, Minnesota . It opened a floodgate of victims who came forward with clergy sex abuse stories across the country.

On Friday, Ramsey County prosecutor John Choi leveled six counts at the archdiocese of Saint Paul and Minneapolis. He accused it of encouraging, causing or contributing to the sexual abuse of three victims by a priest in 2010 and 2011.

Each count is a "gross misdemeanor," and each carries a maximum of one year in prison and/or a $3,000 fine. The complaint focuses on abuse by former priest Curtis Wehmeyer, but it and an accompanying document say his case was just one of many that the archdiocese let slide.

A representative of the archdiocese has been summoned to answer to the complaint in court on June 12.

The archdiocese will cooperate with Choi's office, Auxiliary Bishop Andrew Cozzens said in a statement Friday. "We deeply regret the abuse that was suffered by the victims of Curtis Wehmeyer and are grieved for all victims of sexual abuse," he said.

Felony abuser

Wehmeyer was convicted in February 2013 on 20 felony charges of sexual abuse against minors and possession of child pornography, the archdiocese said in a statement. He was sentenced to five years in prison, and since then has been charged again with similar criminal sexual misconduct.

In 2012, the archdiocese booted Wehmeyer from the ministry. In March this year, Pope Francis permanently ejected him from clergy status.

And Saint Paul Archbishop John Nienstedt promised to do better.

"I am deeply saddened and have been profoundly affected by the stories I continue to hear from victims/survivors of clergy sexual abuse. My focus, and the focus of the archdiocese, is to do all we can to keep children safe while offering resources for help and healing," he said in a statement then.

'Turned a blind eye'

That was too little too late for prosecutor Choi, who said the archdiocese protected Wehmeyer and kept him in its system while he continued abusing children.

"When confronted with disturbing information about Curtis Wehmeyer, church officials time and time again turned a blind eye," he told reporters Friday.

To tackle the problem of sexual abuse by clergy, the archdiocese created the "Promoter for Ministerial Standards Program" in 2005 to supervise offending members. To Choi, it was an empty shell -- or worse.

"What was purported to be a best practice in monitoring and supervising wayward priests was in reality a sham," he said. And news of Wehmeyer's behavior grew worse.

"As time progressed, the information about Curtis Wehmeyer became more alarming and more specific," he said. Much of the 44-page complaint and the 35-page petition are dedicated to Wehmeyer's missteps and problems: From sexual issues, to alcohol addiction, DWIs and illegal drug use -- to uncomfortable approaches made on boys.

Hanging around boys' bathroom

The priest had been seen hanging around the boys' bathroom, and been caught loitering in an area of a park notorious for hook-ups, the documents said.

A priest Wehmeyer had unspecified questionable contact with was keeping his distance, and Wehmeyer had approached children in odd ways, the documents allege.

He once hit on teen boys in a book store, asking one if he was in the mood for sex, according to the documents.

The last incident was reported to the archdiocese, which said it would place restrictions on Wehmeyer and have him evaluated at a treatment center for clergy.

In 2005, he was required to participate in the archdiocese's monitoring program, and although he showed signs he was not complying with it, the program's head let him slip through it, the complaint said.

Prosecutors called the program "window dressing."

Promoted to pastor

With knowledge of Wehmeyer's past, Archbishop Nienstedt later promoted him to pastor.

"Are you aware of my past? Are you aware of my record?" Wehmeyer said he asked Nienstedt at the time. Nienstedt brushed it off, the documents said.

In the two years that followed, he abused at least three more boys on parish grounds, for which he was later convicted.

"During at least the summer of 2010, Wehmeyer sexually abused VICTIM-1 multiple times, including touching the boy's penis and buttocks and exposing himself to VICTIM-1," the complaint read. He gave the boy marijuana and beer, and showed him pornography.

He did the same with a second boy that summer, and a year later, he repeated the abuse with a third boy, getting him high and drunk to the point that he was incapacitated. The boy built barriers with pillows in a bed they shared to keep Wehmeyer away, the documents said. But that didn't work.

Turned in to police

In June 2012, a church deacon turned Wehmeyer in to police, and a mother reported to police the abuse of her two children.

All three boys will require psychological treatment as will a traumatized sibling of one of the boys, the documents said, and prosecutors are holding the archdiocese accountable for that fact due to its "act, word and omission."

The costs for treatment could climb over $100,000.

Wehmeyer's was not the only case the archdiocese swept under the rug, the documents said, which named more examples of clergy who abused children. "Respondent has a long history of not effectively addressing sexual abuse committed by some of its clergy," it read.

But Wehmeyer is the most recent after a long prior history of abuse within the archdiocese, it read, and one of the worst.