Brooklyn Center man pleads guilty in girlfriend's beating death at Plymouth hotel

A Brooklyn Center man pleaded guilty Tuesday to killing his girlfriend last February in a Plymouth hotel room that they shared with their three children and will be sentenced to 19 years this month.

Alex Garfield Keaton, 39, entered the plea agreement Monday in Hennepin County District Court. He admitted to unintentional murder in exchange for dismissing the additional charge of intentional murder, according to court documents. Assistant County Attorney Dan Allard had wanted to exceed sentencing guidelines in the case, and Keaton agreed to the 19-year sentence as part of a plea deal.

Keaton's public defenders Andrew Reiland and Gabriel Bozian declined to comment.

Charges accuse Keaton of beating 41-year-old Lisa Kathleen Petersen, of Buffalo, to death on Feb. 7 at a Red Roof Inn.

The nonprofit Violence Free Minnesota said Petersen was the third of the state's 24 victims of intimate partner homicide in 2022.

Petersen's father and sister could not be reached for comment.

The Hennepin County Medical Examiner's Office said Petersen died of multiple blunt force injuries inside Room 212 at the inn.

The charges further state:

Keaton told police he was in bed when he heard a loud thud and saw a 10-pound dumbbell next to Petersen on the floor.

He said the dumbbell fell on her, causing her death. The eldest daughter also said this. But the autopsy determined her death was caused by "complex homicidal violence."

Petersen's left kidney was torn and there was significant blood in her chest cavity, the medical examiner reported. She had bruises on her arms, chest, legs, face and neck.

"Dropping a 10 pound weight on herself could not cause these injuries and a person could not self-inflict these injuries," the medical examiner stated in charging documents.

"The 16-year-old has a physical disability, making [Keaton] the only person able to deliver such damage to [Petersen] who was in the hotel room at the time she must have suffered her injuries," according to the charges.

Keaton's internet search history and Google account showed that he researched Minnesota sentencing guidelines, defense attorneys and even murder for hire.