A Galveston County jury Friday sentenced a League City man to 80 years in prison for sexually assaulting a 12-year-old boy beginning in 2000, prosecutors said.

Robert Griffin Alexander, 53, was convicted Thursday of aggravated sexual assault of a child after a weeklong trial in Galveston County district court. Jurors returned the 80-year sentence after hearing testimony from additional witnesses who accused Alexander of abuse spanning years.

Alexander abused the victim for about four years beginning in 2000 after meeting the family while serving as the victim’s older brother’s Cub Scout leader, according to prosecutors.

Seventeen years after the abuse began, the victim, then an adult, reported the allegations to police in 2017. Two of his brothers also came forward at the time and reported abuse by Alexander, prosecutors said.

The initial investigation didn’t result in criminal charges. But authorities reopened the case in 2022 after a fourth victim reported being sexually abused by Alexander for about four years beginning in 2010. Additional victims later provided statements to investigators.