WASHINGTON (DC News Now) — Police said a man has been arrested in connection to the death of his 5-year-old son in Northwest D.C. The Metropolitan Police Department (MPD) said on Oct. 6, around 9:45 a.m., officers were called to the Connecticut House Apartments, which is in the 4500 block of Connecticut Ave. They were told a 5-year-old boy was in cardiac arrest. According to court documents obtained by DC News Now, when first responders arrived, they found the boy lying on the floor, unconscious and unresponsive. He was pronounced dead at the scene at 10:19 a.m. DC police investigate shooting in Northwest, victim hospitalized Detectives quickly learned that the boy and his two sisters - both of whom are children - live at the apartment with their father, 32-year-old DeAndre Pettus. A witness who lived nearby and has a Civil Protective Order against Pettus told police that he was upset earlier in the morning. He said his car needed a battery and he was going to catch the bus to get one. She said that Pettus came back and said "I f----- up, [my son] is not breathing I was going to his body and he was trying to run and hit the wall. I f----- up he is unconscious." The witness demonstrated to police that "going to the body" meant Pettus was punching him with full force. She said she had seen him punch the 5-year-old in the past "with force that was not appropriate for a 5-year-old to be punched," court documents read. Officials also interviewed the father's two daughters, sisters of the 5-year-old. They said he was all right the day before, on Saturday. She said that he had "slipped and fell and hit his face, and shoulder on the wall," earlier that morning. She said he was crying and that Pettus, their father, tried to wake him up and did CPR on him before putting him in the shower. She said he thought he was dead because he wasn't breathing, but that his heart was beating when she felt it. The girl said her dad was nice because he got them candy, but sometimes he could be "a little mean." Police investigating death of 5-year-old boy in Northwest DC She reported that he would hit them when they were in trouble. If they were in big trouble, she said he would hit them with a belt. The girl reported that the 5-year-old had once dropped a glass and that Pettus whooped his legs with a belt. Pettus's other daughter said she saw when her brother slipped and fell. Court documents report that she said he wasn't moving and made noises like he was hurt. The 5-year-old boy's autopsy reports that he had two small abrasions to his temples and a faint contusion to the back of his scalp. Otherwise, there were no signs of abuse. His cause of death was declared to be undetermined. On Oct. 7, MPD said authorities charged 32-year-old DeAndre Pettus, of Northwest, with First Degree Cruelty to Children (Aggravated Assault). This is a developing story.