GRAND RAPIDS, Mich. (WOOD) — A 24-year-old has been sentenced for the February murder of a 1-year-old Grand Rapids boy.

On Thursday, Alex John Radulovic was sentenced to 31 to 100 years for the Feb. 5 murder of Alexander Butler. He previously pleaded no contest to charges of second-degree murder and second-degree child abuse.

Around 9 a.m. on Feb. 5, emergency crews were sent to Weston Street SW near Ionia Avenue after receiving reports of an infant not breathing.

According to the court documents, police found Alexander with several bruises on his face, chest and back. The child was taken to the hospital where he died.

His death was determined to be suspicious.

An autopsy revealed that Alexander died of head trauma and his death was ruled a homicide.

GRPD said Radulovic was the boyfriend of Alexander’s mother and was responsible for him at the time of the incident.

Court documents said that when he was interviewed by investigators, Radulovic admitted that he was frustrated because Alexander was fussing and crying. He said he picked the baby up and slammed him against the floor three or four times.