A psychologist has been sentenced to 20 to 30 years in prison for the baseball bat beating death of his sleeping 20-year-old daughter at their Michigan home.

Robert Kelly of Oxford was sentenced Wednesday in Oakland County Circuit Court in Pontiac. He pleaded guilty last month to second-degree murder in exchange for the dropping of a first-degree murder charge.

The Oakland Press says the 53-year-old Kelly wept upon entering the courtroom. He sobbed while apologizing but offered no explanation for the attack.

Authorities say Kelly attacked Megan Roberts on May 9, 2011, then went to the Oxford police station and confessed. She fell into a coma and died July 27.