SIOUX FALLS, S.D. (KELO) — A Sioux Falls man is in police custody, accused of murdering his infant son.

Court documents say the baby, Daxton Castimore, was just eight weeks old.

Officers were called to an apartment in the northern part of the city this weekend for a child who was not breathing.

Dylan Castimore, 22, called 911 late Saturday morning. He told the dispatcher the baby wasn’t moving and was coughing up blood. The infant was pronounced dead at the hospital.

At the apartment, court documents say officers found red smears on a wall and on the floor in a bathroom, along with red droplets on the wall and ceiling of the bedroom, and a red smudge on the carpet.

“Some things on scene seemed consistent that an assault may have occurred,” Lt. Terrance Matia said.

Police interviewed Dylan Castimore at the hospital. He told police Daxton was crying, so he made a bottle and as he tried to feed him, the infant began to stare at the wall and his arms went limp.

But court documents say that’s not what police heard when they listened to surveillance video shot outside the apartment.

Around 11:20 a.m. Saturday, police say they could hear crying, followed by a slapping or hitting sound, more crying and a loud thud. Over the next 20 minutes, police heard more crying and more loud thuds.

At 11:41 a.m., just minutes before the 911 call, police say they could hear the final slapping and hitting sounds and a man saying, “Come on. Wake up.”

According to an autopsy, what happened inside the Sioux Falls apartment was a homicide.

“The injuries were very extensive and would shock most people,” Matia said.

During a news conference Tuesday afternoon, Sioux Falls Police said the father was arrested hours earlier in the day at a relative’s house. He’s being charged with second-degree murder and first-degree manslaughter.

Police say the crime is shocking but there was a lot of good police work done to figure out what happened to the baby boy.