A man accused of killing a 2-year-old western Iowa boy in March by sitting on him has pleaded not guilty to his charges.

Larry Murphy, who is from Omaha, Neb., but most recently lived in Council Bluffs, had his plea to charges of first-degree murder and child endangerment filed Monday morning, according to online court records. The 31-year-old's jury trial in Pottawattamie County is set to begin May 29, court records show.

Calls placed Tuesday afternoon to Joseph Barrett Reedy and Drew Munger, the public defenders assigned to Murphy's case, were not immediately returned.

Murphy was arrested last month after he and his sister called 911 because of an unresponsive child, Oakland Oburu, in Murphy's care.

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Murphy, who was dating the child's mother, had been living with 2-year-old Oburu and his brother and mother at the American Inn motel at 2717 S. 24th St. for about six weeks, according to a criminal complaint filed by Council Bluffs police.

Authorities spoke with the boy's mother and learned that Murphy was the children's primary disciplinarian, because the mother has cerebral palsy. On March 15, Oburu took Murphy's cellphone, and to punish the toddler, the man — listed at 6 feet tall and 160 pounds — allegedly sat on the child, who was on a bed in the motel room.

Oburu would later die at a Council Bluffs medical center. He was described in his obituary as an affectionate toddler who loved his sibling and family.

"He had a smile that would melt anyone’s heart," the obituary reads. "He was a very loving little boy and his family’s world. Oakland had a natural way of stealing everyone’s heart."

His family did not immediately return a call seeking comment.

The mother said Murphy was on the boy for "about 20 seconds," according to police.

"She said her son initially was moaning during this and then became quiet," the criminal complaint states. "She assumed (Oburu) was going to go back to sleep as Larry covered him up with the bed comforter and left the room to pay their motel rent."

The boy's mother said he heard the boy wheezing, but could not check on him because of her physical condition.

Twenty minutes later, the man returned and examined the boy, who was still under the blanket, but did not appear to be breathing, court records show. Murphy called his sister for help; she drove from Bellevue, Nebraska, to pickup the child, and the two headed for a hospital, according to a news release from the Council Bluffs Police Department.

They called 911 while taking the victim in and were told to stop where they could. They parked at the Casey's General Store at 510 23rd Ave., and emergency responders met them there, court records show. Oburu was taken to to Jennie Edmundson Hospital, where he was pronounced dead.

"During the examination at the hospital, it appeared that (the victim) had no obvious trauma to him or any large wounds," the complaint states. "(The doctor) did notice that O.O. had subconjunctival hemorrhage in both eyes, which is a possible sign from being asphyxiated."

Murphy is being held on a $1,025,000 bond.

Follow the Register on Facebook and Twitter for more news. Tyler Davis can be contacted at 515-284-8378, tjdavis@dmreg.com or on Twitter @TDavisDMR.