An 11-day-old boy suffered fatal injuries in his family's home west of the Twin Cities, and authorities said Thursday that they are treating the death as a homicide.

The Midwest medical examiner's office identified the infant as Cassius Charles Ironheart-Proell, but the office has yet to reveal anything about the nature of the child's injuries.

Police were first alerted to the death on Jan. 18 after receiving a call from the Chippewa County Montevideo Hospital late that night about the boy being brought to the emergency room by family members, said Police Chief Adam Christopher.

"Rescue attempts were made by medical staff, but unfortunately the baby was pronounced dead," said the chief.

No arrests have been made, and agents with the state Bureau of Criminal Apprehension have joined the investigation.

The infant suffered his injuries in the home, located in Montevideo, Christopher said. He declined to reveal any further details about the injuries.

The boy lived there with his mother and was the family's only child, the chief said.

Cassius was born Jan. 7 to Demi Smith and Adam Proell, according to the baby's obituary posted online ahead of his funeral on Feb. 6 in Granite Falls, Minn.

"He brought so much joy and happiness to our lives in the very short time that we had with him," the obituary read.

Laura Proell, Cassius' grandmother and mother to the baby's father, said, "I know absolutely nothing; none of us do."

She said that her son, Adam, is "doing all right. It's not a good time for any of us."

Paul Walsh • 612-673-4482