JACKSON, Mich. (AP) – The Michigan Supreme Court has overturned the murder conviction of a man accused of killing his baby son, saying his rights were violated by a hostile judge who repeatedly asked questions at trial.

A judge can interrogate witnesses. But in a unanimous decision Thursday, the Supreme Court said Jackson County Judge John McBain appeared biased and likely influenced the jury, especially when he acted like a prosecutor while questioning a defense expert.

Adam Stevens was convicted of second-degree murder in the death of his 3-month-old son, who had head trauma in 2010. Stevens told jurors that he accidentally dropped Kian after tripping on a toy truck, although he had denied dropping the baby during interviews with police.