An Australian court sentenced a man to life in prison Monday for killing his four-year-old daughter in front of her two young brothers.

Arthur Freeman, 37, was convicted of murdering his daughter Darcey by throwing her from Melbourne’s West Gate bridge on January 29, 2009, during a bitter custody battle with his ex-wife.

Her brothers, aged two and six, watched from the car as Darcey plunged 80 meters into the Yarra River.

Freeman argued that he was mentally impaired when he committed the crime, but Judge Paul Coghlan of the Victoria Supreme Court said Freeman killed his daughter to get revenge on his ex-wife.