The detectives from the Hennepin County Sheriff's Office faced William Jacobs across his dining room table, coaxing him to confront his past. He was 66 years old, a college educator, lawyer and retired chief of the Minneapolis Park Police. He also had a criminal obsession that had finally caught up with him, in the form of thousands of images of child pornography and faded photographs that demonstrated five decades of unfettered access to children.

"How far back do we have to go, Bill?" detective Charles Kelly asked. "Do we have to go back when you were in your rookie years? My God, I hope not."

"I just don't understand what you're trying to say to me," Jacobs replied, according to a transcript of the interview.

"When did you start molesting young guys?"

Jacobs didn't reply that day, but newly released documents reveal how the detectives found their answer. They looked in archives for forgotten letters, called up long-retired camp and school administrators, interviewed growing numbers of men who came forward to say Jacobs assaulted them in lake cabins, summer camp dormitories and his own Deephaven home.

In probing what would become one of the most disturbing cases of serial child molestation in Minnesota, the detectives also uncovered a history of missed opportunities and reluctance to expose a potential scandal. According to the investigative file, obtained by the Star Tribune under the Minnesota Data Practices Act, the detectives learned that in the early 1970s, Jacobs had lost as many as three teaching jobs because he fondled children, yet in each case, his supervisors kept the situations quiet.

They learned that in 1993, after Jacobs rose quickly in his new career as a police officer, a top state law enforcement official heard from someone who was molested years earlier by Jacobs but settled the issue with a private meeting. Jacobs' employer, the Minneapolis Park and Recreation Board, was never told.

Not until a 15-year-old boy came forward to say the man he knew as "Uncle Bill" had been touching him for years did Jacobs finally face the consequences for his crimes. Where so many others had looked away, the teen looked his abuser in the eye in a Minneapolis courtroom. Jacobs was sentenced in May to 18 years after he pleaded guilty to second-degree criminal sexual conduct.

By then, nearly two dozen men claimed Jacobs had abused them as early as 1962.

"It never should have happened to my son, and I hold all of these people accountable," the teenage victim's father said last week. "It makes us sick to know not only the history but all the people in positions of authority that should have stopped this many, many times and didn't."

One of the people who got an early warning about Jacobs was Michael Campion, a former state public safety commissioner. Today, he's unsure whether he could have done more after one of Jacobs' victims came forward in 1993 and urged him to look into the officer's history.

Campion sought a prosecutor's opinion, arranged a meeting between Jacobs and the victim and told Jacobs he would be watching him. But he understands why the parents of the abused teen would think that wasn't enough.

"When you take a person's innocence away, you can't replace that," Campion said. "I don't blame them for being angry with me."

Distress, but no calls to police Jacobs admitted in court that the victims who came forward were telling the truth. Imprisoned at Minnesota Correctional Facility in Faribault, he declined a request for an interview.

In his first career as a teacher at prestigious prep schools, Jacobs' taste for boys kept getting him in trouble. Jacobs' first job after graduating from Northfield's Carleton College in 1965 was at the Taft School, a Connecticut boarding school, then all-male.

In a deposition he gave last May in exchange for being dropped from a victim's lawsuit, Jacobs said he was confronted by the headmaster for inappropriately "approaching" at least one student. Jacobs quietly left the school in 1971. Taft spokeswoman Julie Rieff said the school "has no knowledge of any improper conduct by Mr. Jacobs while at Taft."

He took his next job at the Blake School in Minneapolis. Around 1971, at least two students told their parents they were sexually abused by Jacobs. In his deposition, Jacobs said he was confronted by then-headmaster Jack Edie, who told him to finish the school year from home completing lesson plans.

Blake School spokeswoman Cathy McLane said officials cooperated with investigators and could find no documentation to determine whether Edie, who has since died, notified police of the allegations. But the headmaster did call Robert Telleen, the director of YMCA's Camp Warren in Eveleth, because he knew that Jacobs had worked as a camp counselor there for 10 years.

Edie told Telleen that Jacobs had "pedophilic tendencies," according to Telleen's handwritten notes from the 1972 telephone conversation. "Thing has spread much further," the note said. "Jack trying to decide how to help Bill as a friend now and helping Bill choose another vocation."

From then on, Jacobs was no longer a counselor at Camp Warren. But over the next four decades, he returned to the camp regularly as a volunteer. He brought children to the camp as recently as 2009.

"I have never been so upset about a situation as I have been with Bill," Telleen wrote to his successor at Camp Warren, John Howard, in a letter from 1972. He added later he told no Warren staff about the incident, and that Jacobs "seemed resigned to a new career."

In a response, Howard wrote that he was "astounded" to learn of the allegations about Jacobs, whom many knew as "Jake." "For as closely as I have known Jake over the years, there was no evidence of any sexual hangup at all. I suspect that five years at Taft School were not helpful in this respect."

In an interview last week, Telleen said he moved swiftly to fire Jacobs from Camp Warren based on the Blake incident, but admits he didn't inquire further of staff or campers.

Telleen couldn't say whether he would have done anything different, such as go to the police.

"I don't know why I would have. Look, the times then were extremely different from now. At 31 years of age I'm not sure I'd even heard the term 'pedophile,'" he said. "I did everything in good faith. It was just a time before we really woke up to what could be happening."

That summer 40 years ago, Jacobs took his first steps in a new career, working part time as a patrol agent for the Minneapolis Park Board. But he kept teaching as well. In 1973, he got a job as an eighth-grade science teacher at Breck School. In 1975, laws went into effect that required reporting of suspected child sexual abuse to the authorities.

In December 1974, a 13-year-old Breck student reported to his parents that Jacobs molested him during an overnight stay at the teacher's house. The victim and his father went to Jacobs and then-headmaster John Littleford, but what happened next is a matter of dispute.

In his deposition, Jacobs said that he was allowed to finish the school year, as long as he promised to keep his behavior under control. He went on to say he kept teaching part time at Breck, only losing his job when he was caught molesting another child the following year.

School records also indicate Jacobs was employed until 1976.

But Littleford said that when he arrived at Breck for the 1974-75 school year, he knew nothing about Jacobs' past. "I fired him later that same year, with the advice and support of legal counsel," Littleford said in an e-mail to the Star Tribune.

Littleford, now an educational consultant in Louisiana, declined to comment further. His attorney, Daryle Uphoff, called Jacobs' claims false and said Jacobs merely wants revenge on Littleford for firing him.

"Mr. Jacobs' life is a lie and I wouldn't expect that to change any," Uphoff said.

Campion's role In 1993, then-Minneapolis Police Chief John Laux received a letter.

"I have a question regarding Bill Jacobs," the man wrote. "Was his rise to high rank in the Minneapolis Park Police with, or without your knowledge that he has a history of sexual abuse of children?"

The letter went on to detail how he and his brother were molested at Camp Warren in the 1960s when Jacobs was a counselor.

Laux, who had no authority over Jacobs, asked Campion, then assistant superintendent of the Minnesota Bureau of Criminal Apprehension, to investigate.

Campion called the man. In a transcript of a telephone conversation, he acknowledged that it was too late for Jacobs to be charged with sexual abuse.

"I guess it just gave me more pause to worry when I realized he was in a position of more and more responsibility and power," the man told Campion, according to a transcript of a 1993 telephone conversation. He continued: "I just think it's wrong that so many of us have stayed quiet for so many years and allowed him not to face the consequences."

He urged Campion to look into Jacobs' history.

"I mean for instance, like checking out his work, his past as a school teacher, different prep schools. Are you going to have the time or the energy to do much digging?" the victim asked, according to the transcript.

Campion told the man: "I think in fairness to whoever it might be and certainly not because he's in the law enforcement business, but allegations of this nature can be extremely damaging. That's kind of a delicate line that we have to try and navigate through."

Still, Campion brought the case to the Minnesota attorney general's office, who said there was nothing they could do for such an old case. He arranged a meeting with the victim and Jacobs that ended with a letter of apology. Campion said later that he believed the victim and kept a file on the incident. When Jacobs was charged in 2010, he immediately called investigators.

'I want it to stop' Nearly 17 years would pass before a teenager tearfully told his mother a secret about the family friend who for years had taken him camping, to sporting events and on overnight stays at his Deephaven home.

"Mom, Bill has been touching me since I was in sixth grade. I want it to stop," he said, according to investigative reports. "There may be others. I want to be able to protect them."

Within days, sheriff's detectives arrived at Jacobs' house to build their case. This time, authorities were determined to uncover the full scope of Jacobs' crimes.

In the end, 22 people came forward, each with the same story: After earning their parents' trust, Jacobs had fondled them at sleepovers at his home, at Camp Warren in Eveleth, even on road trips.

"For me, the biggest fear or horror is that there's the situation that happened with me," one victim, 48, told investigators. "But I just can't even imagine what may have happened to so many others."

Moments before his trial was to begin in April, Jacobs walked into the courtroom and saw his accuser, then 17, sitting in the witness stand. Jacobs, taken aback, placed a hand to his chest. The teenager stared at Jacobs and refused to look away.

Moments later, the attorneys met again. Jacobs would plead guilty.

Assistant Hennepin County Attorney Judy Johnston called it the boy's bravest act of many, done for more than just himself and the generations of victims that came before him.

"He felt more strongly that he was standing up for the people after him," she said.

Staff writer David Chanen contributed to this report. Abby Simons • 612-673-4921