A former St. Paul school janitor will spend 10 years in prison after admitting to multiple sex abuse crimes.

Walter Happel, 63, pleaded guilty Thursday to four separate charges – one relating to an incident when he was accused of peeking at a St. Paul elementary school student; the other three in connection with sexually abusing both his nephew and a neighbor child, crimes that date back to the 1980s.

Happel was sentenced to 10 years in prison as part of the plea deal, which the Ramsey County Attorney's Office says is above the sentencing guidelines for when the crimes took place. He'll be officially sentenced May 7.

“This defendant, Walter Happel, has preyed on the innocence of children for over 30 years, and I am relieved that we can now hold him accountable for his crimes,” Ramsey County Attorney John Choi said in a statement, noting his victims now won't have to testify in court during a trial.

Original charges

Happel was initially charged in March of 2014, after he reportedly looked both under and over the stall door and smiled at a boy as he used the toilet at a school in St. Paul.

Those reports prompted Happel's son to contact police, and he told investigators that Happel sexually abused him, other family members and a neighbor child growing up, the Ramsey County Attorney's Office said.

The attorney's office says most of those cases weren't included in the charges because they're past the statute of limitations.

The counts Happel pleaded guilty to:

One count of criminal sexual conduct in the First Degree; one count of interfamilial sexual abuse in the fourth degree; and one count of interfamilial sexual abuse in the second degree. All were for sexual abuse incidences involving a neighbor child and Happel's nephew.

He also pleaded guilty to one count of surreptitious invasion of privacy in connection with the February 2014 incident at the St. Paul elementary school.