POLK COUNTY, Fla. - A central Florida man has been sentenced to life in prison for killing his grandmother.

A Polk County judge sentenced 25-year-old Christopher Whaley on Thursday after a jury convicted him of first-degree murder.

Prosecutors say Whaley stabbed 69-year-old Barbara Denmark more than 20 times as she took a bath at her Lake Wales home in April 2012. Deputies responded after Whaley called 911 and reported finding him kneeling near Denmark's bloody body, cradling her head.

The Ledger reports that Whaley told investigators he had gotten into an argument with his family earlier in the day. He planned to kill his grandmother, then go to his aunt's house and kill everyone inside.

Whaley told deputies that he did not want to kill his aunt after hearing his grandmother's expressions of love as she was dying. He said his plan was to walk to his aunt's house and kill everyone who was there.

Instead, he told police that his grandmother's words led him to call 911 and say, "Come get me."

Defense attorneys argued that the killing wasn't premeditated, and that Whaley had just snapped.