A West St. Paul dad has been charged with first-degree assault after his 4-month-old daughter was taken to a hospital with multiple skull fractures and bleeding in her brain and eyes.

Michael J. Mason, 26, kept adding to his story of how the baby was hurt, according to court documents. First, he said he had tripped over a chair on his way to put his daughter in her crib on Feb. 17 and she hit her head on a baby swing during the fall. He said the baby threw up after getting a bottle, but his phone was broken and he couldn't call anyone.

Mason and the baby's mother took the girl to be examined the next day. Doctors found she had bleeding on the brain and in her eyes and three or four skull fractures "consistent with nonaccidental trauma," the criminal complaint said.

The defendant then admitted that he'd shaken the baby but "in a playful manner" before he tripped while carrying her. Later, when a detective challenged his story, Mason said the baby's head "kind of bounced off the floor ... more than once" while he was playing with her, the complaint said.

The baby lost consciousness for 10 or 20 minutes, Mason told police. He claimed he was "freaking out" and dropped her two more times, then fell partly on top of her, the complaint said.

Mason admitted he was angry with the baby's mother because she had misplaced his car keys, which he needed to move his vehicle before he was towed. He didn't tell the mom about their daughter passing out or hitting her head on the floor, he told a detective.

West St. Paul police Lt. Brian Sturgeon said the baby is still hospitalized and faces a long road to recovery. Doctors don't know yet whether she will have any long-term damage.

Mason made his first appearance Friday in Dakota County District Court. His next court date is March 18.