FOREST HILL, Texas — The man who rammed his car into a church then beat the pastor to death with an electric guitar apparently suffered from a mental illness, his widow said.

Speaking after a prayer vigil Tuesday night for the Rev. Danny Kirk Sr., Shanellia Harris Birdow said she does not know why Derrick Anthony Birdow attacked the minister the previous day. She is a member of Greater Sweethome Missionary Baptist Church in this town near Fort Worth, but he had attended only a few times and did not know the pastor, she said.