The St. Paul (Minn.) Pioneer Press reported that surgeons separated Jordan and Jacob James in November, and that Jacob, the stronger twin, was released to his parents' care Jan. 3 while his brother remained at Mayo.
On Jan. 11, the twins' parents, Robert Heck, 26, and Valerie James, 19, took Jordan to the emergency room, where a doctors discovered 24 broken bones -- eight leg fractures estimated to be 7 days old and 16 rib fractures that looked more recent, the newspaper reported.
Both parents were charged Monday with felony first-degree assault, aiding in the crime and obstructing justice, the newspaper said. They were not arrested.
According to the criminal complaint, both parents denied knowing how the injuries occurred but theorized a car seat could have hurt Jacob, the Pioneer Press reported.
Another resident of the Ronald McDonald House told police Heck was heard yelling, "Stop it, stop it. I have had it. That's enough. ... Knock it off," the day before the couple sought emergency care for their baby, the newspaper said.