Florida teen, 19, guns down his father and then executes his mother in front of cops

A 'monster' teenager shot down his father and then executed his mother at point-blank range in front of cops before dying in a police shootout.

Police say they received a call just after 11pm on Saturday from a woman - later identified as Rebecca Ann Themelis, 48 - informing them that her husband, Christos Byron Themelis, 51, had been shot.

More gunshots could be heard while she was on the phone with the dispatch center, the Hillsborough County Sheriff's Office reports.

By the time deputies arrived at the home on Cactus Wren Place in Tampa, Florida, they found the suspect - Christos Alexander Themelis, 19 - and his mother, Rebecca, outside.

As deputies watched in horror, the suspect shot his mother in the back of the head and began shooting at the officers, injuring one deputy, the sheriff's office said.

Dramatic body camera footage caught the stand-off between Christos Alexander and the deputies, beginning when they arrived on the scene and found him outside with his mother.

'Show me your hands, show me your fucking hands,' Deputy Shane McGough, 26, could be heard yelling.

He then pleaded with Rebecca to 'get out of the house now' and walk towards him, holding his gun drawn before radioing in, 'he's got her at gunpoint.'

'Listen, we don't want to hurt you, just let your mom walk to us, let her walk to us OK?' McGough tells the suspect, repeating his instructions to 'keep your hands up' and 'do not reach behind your back.'

As the son apparently retreats to go and grab his gun, McGough once again pleads with the mother to 'walk to me, walk into my flashlight.'

Then when Christos Alexander comes back out with the gun, he pleads, 'Ma'am get away from him now and come here.'

Seconds after begging the suspect to 'stop reaching into your waistband', gunshots can be heard in the bodycam footage as both sides exchanges fire.

McGough was struck in the leg, yelling 'I've been hit' at his fellow officers and asking for a tourniquet.