Gilbert police have arrested a man after his baby son suffered multiple broken ribs and other serious injuries while in his care.

Nathan Clapp, 36, faces one felony count of child abuse.

Police say his 3-month old son suffered seven rib fractures, a head bleed, a lacerated liver, fluid in his lungs and a bruise on his head.

The baby was brought to Cardon Children's Hospital on August 12, and a social worker reported the suspicious injuries to police.

The young victim had been in the care and custody of Clapp, who is his biological father.

The baby's mother, Clapp's live-in girlfriend,  had reportedly just gone back to work, leaving Clapp to care for the baby and several other children.

Clapp offered police several explanations about what might have happened to the baby, including the possibility he rolled over on the victim while sleeping, or that the young victim may have "tripped over a small red chair in the kitchen," according to the police report.

But later, police extracted data from Clapp's cell phone that indicated Clapp had "complained about the victim being fussy and crying all the time," and that he was "getting frustrated and this was the type of thing that makes a parent hurt their child," according to the police report.

The police report also states that a pediatrician examined the young victim, and determined that the posterior rib fractures "can only be caused by an intense squeezing of the chest," and that the lateral rib fractures "can be caused by squeezing or blunt force trauma."

Clapp is due back in court September 5.

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