A Petaluma man will be spending 15-years-to-life behind bars for sexually abusing a young boy. Brandon Cooper received his sentence yesterday according to the Sonoma County District Attorney’s Office. He will be serving an extra nine years on top of the of the 15-years-to-life sentence. He was convicted for abusing a child under the age of 10 “for years”. Cooper was previously convicted of sexually abusing a friend’s developmentally delayed relative.