A former Burnsville scoutmaster already convicted of repeatedly sexually abusing one Eagle Scout when he was a minor pleaded guilty on Friday to sexually molesting three other scouts in his troop.

The plea from Peter Stibal II came in an arrangement in which he was sentenced to more than 21 years, with 14 years of that to be served in prison.

He'll be on conditional release for seven years after that, to be followed by 10 years on supervised release. Violations could send him back to prison.

Stibal, 46, of Burnsville appeared sad and looked away during statements from victims and their parents. Weeping, they told of betrayal and manipulation by a predator skilled at gaining trust.

"I'll ask myself forever, why did this monster enter our lives?" said the mother of one molested boy. The Star Tribune typically does not print the names of abuse victims or their families.

The woman and other parents told the judge of the guilt they feel for not realizing what was happening to their sons, who kept the secret for years until one stepped forward in 2009.

Her teenage son told how Stibal took advantage of his trust. He and his mother said Stibal stripped the boy of his innocence and youth.

"Where's the fairness when something I've lost can't be replaced?" the scout asked.

In addition to the pain, guilt and violation of trust, Stibal tarnished the name of the scouting organization as it tries to overcome such problems, parents and Chief Judge Edward Lynch said.

In all, Stibal pleaded guilty to two counts of first-degree criminal sexual conduct and five counts of second-degree criminal sexual conduct involving four scouts under his care in Burnsville Troop 650.

The assaults happened between 2003 and 2008, when they were ages 11 to 14.

Stibal had agreed to an Alford plea of guilt, in which he maintained his innocence but agreed that there was a high likelihood he'd be found guilty in the upcoming trials.

County Attorney James Backstrom said he was reluctant to accept Stibal's pleas because he still says he's innocent. Yet prosecutors wanted to spare three more scouts the trauma of testifying, Backstrom said.

He said it was clear from Stibal's pleas on Friday "that he still has a long way to go" before accepting responsibility for his crimes.

In May, a jury convicted Stibal of two counts of first-degree and two counts of second-degree criminal sexual conduct involving the Eagle Scout who first stepped forward, saying he worried that Stibal was molesting other scouts. He's now 21.

Stibal will avoid not only three more trials for the molestations but also a fourth trial for possession of child pornography. He entered an Alford plea to one child-porn count; five other counts were dropped.

The deal avoided a life sentence, which would have been possible if Stibal had been sentenced consecutively on each of the eight counts for which he was convicted, said his attorney, Fred Bruno.

"Based on the verdict [in May], this was the best thing to do," Bruno said. "We thought long and hard about it."

Stibal's family owned a cabin in Paynesville, Minn., where he was accused of sexually assaulting some scouts, and he owned a Burnsville townhouse, where other assaults occurred.

The townhouse is where police say they found 161 images and 64 videos of child pornography after seizing Stibal's computer equipment during a search in October 2009, prosecutor Amy Schaffer said.

Stibal will be required to register as a predatory sex offender.

In addition, he's received notice that he's being sued by the victims. They're represented by St. Paul attorney Jeff Anderson, who has become internationally known for filing suit in cases where members of the clergy or scouts have engaged in child sex abuse.

Joy Powell • 952-882-9017