O'Callaghan told Montgomery County investigators he had been caring for the child while his wife was out of town when the boy fell backward in the shower and hit his shoulder, according to documents. The following day, O'Callaghan said, he put the boy down for a nap, but when he went to check on him, the child had mucus coming from his nose and began vomiting while unresponsive after he was picked up, police said.