Police say a 41-year-old woman was fatally beaten while in a Plymouth motel with family members last month.

Lisa K. Petersen, of Buffalo, Minn., died on Feb. 7 shortly before 2 a.m. at the Red Roof Inn in a room that also was occupied by a man and their three children, read a search warrant affidavit filed by police in Hennepin County District Court.

The Medical Examiner's Office disclosed Monday that Petersen suffered "multiple blunt force injuries" while in the motel, located in the 2600 block of N. Annapolis Lane.

Police were told by the man with Petersen that she dropped a dumbbell on herself, but the autopsy determined that her "trauma ... was not consistent with" his explanation, the affidavit read.

"The preliminary finding was that Lisa likely died as the result of homicidal violence," the filing continued, based on the autopsy, which uncovered bruises on her arms, chest, legs, face and neck.

Also, the filing pointed out, "the deceased had numerous significant injuries that were in various stages of healing."

Charges in connection with Petersen's death have not been filed, and no one has been arrested.

At the room, police seized cellphones belonging to Petersen and the man, two 10-pound dumbbells, black rope, scissors and handwritten notes, the filing read.

According to the search warrant affidavit:

The man in the room told a detective that he was in bed and Petersen was on the floor, then he heard a loud thud. He said he got out of the bed and saw a 10-pound dumbbell next to Petersen, who complained of sore ribs and told him, "I can't breathe."

He said Petersen hit her head on a table as he and one of the children were helping her off the floor in an effort to take her to a hospital.

The man said he picked up a limp Petersen and headed for the car, but he went back in the room and began cardiopulmonary resuscitation while one of the children called 911.

Motel video surveillance captured the man leaving the room at 1:22 a.m. while carrying Petersen's body, which "displays no sign of life at that time," the court document read. He walked out of the camera's view and was back in the room with a minute. Police arrived at 1:29 a.m.

Asked by the detective about marks on Petersen's neck, the man said she tied a rope around her neck two days ago that he cut off.