SPRINGFIELD TOWNSHIP, Mich. (AP) — Authorities say they believe they've found the body of a 15-year-old boy who was sought following the stabbing death of his 65-year-old grandmother in suburban Detroit.

The Oakland County sheriff's department got a call early Tuesday from a man reporting the woman had been stabbed and his son had left a note saying he was going to kill her. She was found with multiple stab wounds in her bedroom in the Springfield Township home.

The department says the woman's car was found in the village of Holly and a body believed to be that of the boy was found on railroad tracks. They say the body had been hit by a train.

Investigators found a large kitchen knife at the home that's believed to have been used in the killing.