Details have emerged of the violent past of an anti-Republican fanatic who shot a US congressman at a practice session for a charity baseball match. 

James T Hodgkinson, 66, died after a shootout with police on Wednesday after he opened fire at a sports field in Alexandria, Virginia, where Republican lawmakers and their aides were training for a charity baseball game.

US Congressman Steve Scalise was shot in the hip and remains in a critical condition in hospital. Two police officers were also injured.

The gunman, who was an ardent supporter of failed Democrtic candidate Bernie Sanders, frequently criticised both President Donald Trump and Hillary Clinton on his Facebook page.

Hodgkinson was arrested for battery, domestic battery and discharging a firearm in April 2006.

He allegedly dragged his 16-year-old foster daughter by the hair and beat her, before punching her female friend in the face and hitting a boy in the head with his shotgun, court documents show. Hodgkinson then allegedly fired his gun as he ran away.

A day earlier, he allegedly damaged a door while looking for his foster daughter at a neighbour’s home.

US President Donald Trump is pictured with US Congressman and Majority Whip Steve Scalise in March. Photo: Getty

All the charges were later dismissed when none of his alleged victims appeared in court, the BBC reported.

A complaint had also been made against Hodgkinson in March this year after he fired 50 rounds into a wooded area near homes.

Hodgkinson moved suddenly to Washington DC from Belleville, Illinois, suddenly after Mr Trump was elected.

Former Alexandria mayor Bill Euille told The Washington Post he’d seen Hodgkinson use the showers at a local YMCA gym and said he appeared to be homeless.

“He’d open up his gym bag and in it, he had everything he owned. He was living out of the gym bag,” Mr Euille said.

“He sat in the Y’s lobby for hours and hours.”

Hodgkinson had slammed Mr Trump on Facebook and reportedly wrote: “You are Truly the Biggest A** Hole We Have Ever Had in the Oval Office”.

WARNING: Harrowing video captures moment of shooting during this morning's GOP baseball practice in Virginia: https://t.co/cNjAs2gSbM pic.twitter.com/V7XoyAGHfj

— Good Morning America (@GMA) June 14, 2017

He was a supporter of former Democratic candidate Bernie Sanders and is believed to have volunteered for his campaign.

Mr Sanders condemned Hodgkinson’s actions on Wednesday.

“I am sickened by this despicable act. Let me be as clear as I can be. Violence of any kind is unacceptable in our society and I condemn this action in the strongest possible terms,” Mr Sanders said in a statement.

An FBI officer collects evidence at the site of Wednesday’s shooting. Photo: Getty

“Real change can only come about through nonviolent action, and anything else runs against our most deeply held American values.

“My hopes and prayers are that Representative Scalise, congressional staff and the Capitol Police Officers who were wounded make a quick and full recovery. I also want to thank the Capitol Police for their heroic actions to prevent further harm.”

Mr Trump said Mr Scalise was “a true friend and patriot”.

“Just left hospital. Rep. Steve Scalise, one of the truly great people, is in very tough shape – but he is a real fighter. Pray for Steve!” Mr Trump wrote on Twitter.

“Rep. Steve Scalise of Louisiana, a true friend and patriot, was badly injured but will fully recover. Our thoughts and prayers are with him.

-with agencies