A 30-year-old Duluth man with a history of domestic abuse admitted in court that he suffocated his 13-month-old daughter because she fussed so much.

Christopher D. Peterson pleaded guilty Monday in St. Louis County District court to second-degree murder and will receive the maximum 40-year prison sentence for killing Layna Rose Peterson after he laid her down on the night of July 5 in the family's home.

"Today is all about justice for Layna," Assistant St. Louis County Attorney Jessica Fralich, who prosecuted the case, said in a statement issued after Peterson's admission. "Mr. Peterson's plea afforded Layna's family the ability to hear from him directly about the heinous crime that he committed. The county attorney's office is hopeful that this will in some way allow the family to begin the long road of healing from this tragedy."

The child's mother, Amber Gundy, found Layna unresponsive shortly before noon on July 6 and called 911. The child was dead when police arrived.

Peterson told police three weeks later that he would frequently become frustrated with his daughter's crying and to stop her from fussing he would quiet her by placing his hand over her mouth and pinching closed her nostrils. He added that he didn't mean to kill her.

Peterson first drew scrutiny by the county's child protection services in December, when bruises along Layna's jaw line were detected during a medical exam, according to agency records requested by the Star Tribune. Peterson explained to authorities that he grabbed his daughter by the jaw in an effort to control her mouth while feeding her a bottle.

While the agency said this injury was sufficient for it to provide services to the family, law enforcement said the action did not rise to the level of a crime.

The agency's involvement with the family was still active at the time Layna died. Based on the death and findings by investigators of illicit drug use by the parents, child protection services sought to terminate Peterson's parental rights to his other children.

In March, Peterson was convicted of a misdemeanor after choking Gundy. He was sentenced to 90 days in jail, a term that was stayed for one year and he was placed on probation. Causing Layna's death violated the terms of his probation.

On Wednesday in Duluth, the newly appointed Governor's Task Force on the Protection of Children will hear public testimony about Minnesota's child protection system.

"We want members of the public to share their experiences and thoughts about how we can better protect children," said Human Services Commissioner Lucinda Jesson, who co-chairs the task force.

The task force was created by Gov. Mark Dayton last month in the wake of a Star Tribune report about a 4-year-old Pope County boy who was killed by his stepmother despite repeated warnings to child protection. It is charged with making recommendations to the next Legislature, aimed at improving the child protection system.

Star Tribune staff writer Brandon Stahl contributed to this report. Paul Walsh • 612-673-4482