MINNEAPOLIS — Minneapolis police have arrested a 21-year-old man in connection with the death of his 4-month-old daughter, who was discovered lifeless inside of a duplex after suffering assault wounds.

The girl was brought to Hennepin County Medical Center after police discovered her inside the eastern Minneapolis home Saturday evening. The girl’s father was arrested and remained jailed on Sunday, according to a press release.

Police said the 21-year-old man was home alone with the child at the time, and that there are no other suspects. She’ll be identified after the county medical examiner completes an autopsy to determine her cause of death.

Police responded to an emergency medical call at the duplex. It’s unclear who placed that call or what type of injuries the girl suffered.

Neighbor Brittney Thomson said the man was “out of it” earlier in the day Saturday, wandering aimlessly and standing inattentive as he let out his two dogs. She said she hadn’t seen the baby at all Saturday, and watched later as paramedics and other first responders arrived at the house at about 5 p.m.

“A paramedic carried (the baby) out by the armpits,” Thomson said. “Originally, I thought it was a doll.”

She said police later coaxed the man outside of the house. She said police handcuffed him without any resistance.

It was the fourth homicide in Minneapolis in the last week.

“In a perfect world, there would be no crime,” officer Corey Schmidt, a police spokesman, told reporters Saturday night. “We are going to investigate this like every other case.”