A 'REMORSELESS' killer bludgeoned his mum to death with an axe then sliced open her chest and ripped out her heart, it is alleged.
Omar Pettigen then performed a solo sex act over the lifeless body of 64-year-old Nailah Pettigen as a "release", according to reports.
And Pettigen, 31, revealed to detectives how the shocking killing felt "good".
He even went out for a few beers with a friend hours after the murder, say cops, who claim he showed no remorse.
Retired maths teacher Nailah was found dead at the flat she shared with her son in Fremont, California, on September 29.
Cops were greeted with the gruesome scene of her dismembered body with her underwear around her ankles, on the bedroom floor.