Vic slap cop hopes to dodge conviction

A Melbourne policeman who slapped a handcuffed teenager five times in the face argues he shouldn't get a criminal conviction because he's a "sick man" with post traumatic stress disorder.

Gareth Gutierrez, 33, has been found guilty of common assault for slapping the 16-year-old in May 2015 after coming to the aid of two female police officers in the western suburb of Kurunjang.

The now-suspended policeman was acquitted of intentionally and recklessly causing injury relating to capsicum-spraying the youth, with a jury accepting he was either acting lawfully or in self-defence.

Gutierrez's "threat detection systems" had become distorted from a 12-year career witnessing traumatic events, the County Court of Victoria was told on Wednesday.

He went to the aid of two policewomen who had been called to a suspected burglary, handcuffing one of the boys, pepper-spraying and hitting him.

The boys claimed they'd been playing an innocent game of football but a resident mistook one of them for a burglar, punched him and performed a citizen's arrest.

Psychiatrist Joe Black told the court Gutierrez struggled to come to terms with what he had witnessed during his career, including "mangled and dead bodies" and a "huge number of traumatic incidents".

He said the officer had remained untreated for a number of years and attempted suicide in 2014.

Dr Black said he believed there was a "considerable price to pay" for identifying as someone with a mental illness in an organisation such as Victoria Police.

He claimed people with PTSD could over or under react in threatening situations when deciding what level of force to use.

Barrister Geoffrey Steward said Gutierrez's moral culpability should be reduced given his PTSD.

He said a few days before Gutierrez attempted suicide, he put his hands around the throat of a man who had threatened to kill the officer's family.

Mr Steward said it was clear Gutierrez was not fit for operational duties in the police force at the time.

"He's a sick man," he told the court.

The matter was adjourned to a date to be fixed.

Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14. Suicide Call Back Service 1300 659 467.