A former FBI informant stabbed Derek Chauvin, the ex-police officer who was convicted for murdering George Floyd, according to court documents filed on Dec. 1. John Turscak, 52, stabbed Mr. Chauvin 22 times with an "improvised knife" in federal prison in Arizona, according to the documents. Mr. Turscak was subdued by responding corrections officers. Mr. Turscak later told officers he would have killed Mr. Chauvin if the officers had not responded so quickly, federal prosecutors said in the documents. The stabbing took place on Nov. 24 at about 12:30 p.m. Mr. Turscak waived his Miranda rights and told FBI agents...