Arlee Hayes III, 25, has been sentenced to 15 years in prison for the drowning death of his girlfriend's 22-month-old daughter in St. Louis.

Sophia Sanchez drowned in a bathtub in May 2009 after Hayes repeatedly beat her, officials said.

An autopsy showed that the girl suffered at least 18 blows before her death, according to testimony.

Hayes, who fathered a different child with Sophia's mother, was alone with the two children at their home in the 7300 block of Vermont Avenue when Sophia died, officials said.

In June, Circuit Court Judge Angela Turner-Quigless found Hayes guilty of second-degree murder and abuse of a child.