Melissa Jenkins admitted a lot of startling things in an Ada County courtroom Monday — including how she helped hide her beaten and bruised 8-year-old son from family members and Idaho Department of Health and Welfare workers in the summer of 2009.

Jenkins, 31, said she saw her boyfriend, Daniel Ehrlick, hit her son Robert Manwill with his hands and a board that summer. Her lawyers say Robert himself told Jenkins that the 260-pound Ehrlick dropped a knee on the boy’s stomach as part of a punishment called “dead bugging,” where the boy had to lie on his back with his hands and feet in the air.

Jenkins said she failed to protect her son and that by allowing him to be left alone with Ehrlick on July 24, 2009 — the day the boy was reported missing — she was guilty of a charge of aiding and abetting murder of the second degree.

Ehrlick is still charged with first-degree murder.

The questions that Jenkins did not address at all, though, were why she allowed such abuse to happen to her son and why she didn’t tell police about it.

There was also no testimony — or information in court documents — on when Jenkins knew Robert Manwill was dead, whether Ehrlick made any confessions to her, or whether she had any idea what happened to the boy’s body before he was found in an irrigation canal.

Those answers may come Aug. 11 — the day scheduled for her to be sentenced. Prosecutors are asking for her to serve 25 years in prison without the possibility of parole, though she can ask for less fixed time. If the judge agrees to the sentence, Jenkins — who previously pleaded guilty to a misdemeanor for injuring Robert’s infant brother — will be in her mid-50s when she is released.

Her youngest boy has been adopted and her daughter lives with her father.

Ehrlick’s trial is set to begin April 27.

Jenkins entered her guilty plea Monday morning, just before 386 prospective jurors were to be brought to the Ada County Courthouse.

Jenkins, who was originally charged with first-degree murder, pleaded guilty to the lesser charge as part of a plea agreement with Ada County prosecutors.

Rob Chastain, Jenkins’ attorney, told a judge Monday that Jenkins believed Ada County prosecutors could prove beyond a reasonable doubt that Ehrlick killed Robert Manwill, which factored into her decision to plead guilty Monday.

Ada County Prosecutor Greg Bower said the plea was good news for the residents of Ada County for several reasons:

Æ With Jenkins’ guilty plea, she finally took some responsibility for what happened to Robert.

Æ The community that rallied around Robert — including more than 2,300 volunteers who helped search Boise when the boy was reported missing in July 2009 — finally has some answers.

Æ Robert’s family and friends — and the public — will be spared a long, graphic and costly jury trial for Jenkins.

Bower said the plea agreement was the direct result of good work by his prosecutors and police who worked on the case.

“They shaped the playing field so that (Jenkins) had no other option,” Bower said. “It’s been a long road. I think our ability to get a guilty plea with a 25-year sentence shows how strong the case is.”

The plea agreement does not stipulate that Jenkins has to testify against Ehrlick at his trial, but it doesn’t have to, Bower said.

Fourth District Judge Darla Williamson ruled in July that prosecutors can compel Jenkins to testify against Ehrlick by offering her “derivative-use immunity” — which means that whatever prosecutors learn from that testimony couldn’t be used against her in her trial.

Bower said if prosecutors want to call Jenkins as a witness in Ehrlick’s trial, that ruling allows them to.

When Jenkins’ attorneys were fighting that request last summer, part of their defense was that Jenkins was a “self-admitted and diagnosed compulsive liar.” Chastain, her own attorney, told Williamson in July he didn’t think Jenkins could give reliable testimony.

Prosecutors said then that if they compelled Jenkins to testify, it would likely only be about statements she made that can be corroborated by other witnesses — such as how Robert appeared to be injured and in need of medical help the day he went missing.

Court documents revealed last year that the boy was suffering from multiple pains that morning — in his head, chest, stomach and back — and his complaints coincided with the appearance of a large hole in the sheetrock wall of the family’s apartment

Boise defense attorney D.C. Carr said, in general, when a co-defendant enters a guilty plea in high-profile case, it’s usually not good news for the defendant who is left.

“It’s a formidable challenge (for the defense), that’s for sure,” Carr said. “It’s kind of like (prosecutors) recruited (Jenkins) for their team. They can say, ‘she was there, she can tell you what happened.’”

But Carr said there can be a risk if a jury really doesn’t like the witness.

Lawyers are careful, for example, in how they use confidential informants in drug cases.

Amil Myshin, Ehrlick’s public defender, said last year their defense was simple — that Ehrlick didn’t commit murder and that prosecutor’ evidence comprised “one of the thinnest first-degree murder cases I have seen in years.”

Myshin said that for all the thousands of documents and other evidence he examined in the case, the main reason Ehrlick is charged is because of statements Melissa Jenkins’ made to others.

Patrick Orr: 373-6619