Medical student, 26, is left horrifically-injured after being pushed into lake by friends even though he couldn't swim - with group then watching him drown for 20 minutes

The family of a promising young medical student are demanding to know why no-one has been arrested for pushing him into a lake and leaving him to drown.

Video filmed at the scene showed the group of friends casually peering into the water as Christopher Gilbert, 26, who could not swim, fought for up to 20 minutes to save himself at the lake in Farmerville, Louisiana.

His heart and breathing had stopped by the time patrons from a nearby restaurant saw what was going on, hauled him to the surface and began CPR.

The group of friends told police he 'just kind of fell face first into the water' before one admitted that she had shoved him off the pier.

'In the legal field, we characterize things the way we see fit,' said family lawyer Claudia Payne. 'Of course, they are saying horseplay. We are saying that it was a criminal intentional push into the lake.'

Gilbert's mother, Yolanda George, said she was alerted when one of the friends rang her at home.

'She told me that Chris had fallen into the lake and he had been underwater for 20 minutes or so,' George told Fox8.

'And I was like, 20 minutes? Why was he underwater for 20 minutes?

'And she was just crying hysterically and he was being airlifted to Shreveport.

'And initially when my son got there the doctor called us in and told me that at this time he was brain 'dead pretty much, and the rest of his organs were starting to fail.'

George raced to the center where she found her son clinging to life.

'I was devastated, I felt like my life had ended in a moment,' she said. 'My son is aspiring to be a medical doctor, he got his masters last year. My son is so sweet, the most selfless being you'll ever meet, I was in a terrible state.'

Outside she found some of the group in the hospital waiting room.

'The friend group came to the hospital still telling me the same fabricated story that he fell,' she said.

'I learned at that moment in the ER, the sheriff called me and he said 'are you familiar with what happened?

'And 'yes he was at the lake and he fell', and he was like 'no, one of the young ladies pushed him'

'And I was like 'who pushed him?' And I started looking around the room, 'which one of you all pushed him?

'The young lady like 'I did', and I was 'Why would you push my son in the lake knowing he couldn't swim?

'She said, 'Well ma'am I didn't know that man couldn't swim', and I was like 'who is 'that man'?

'This is supposed to among a group of friends. 'Who is that man?' Chris.

'Everyone knows he can't swim. He jokes about not being able to swim, even when we went to the restaurant the owner of the restaurant stated everybody knows Chris can't swim, he's been coming here for two years he's always joking about it.'

The video shows that at one point a woman in a black bikini followed Gilbert into the water but without returning with the drowning man.

Sgt Ashley Rhodes of the Union Parish Sheriff's Office arrived at the lake to find restaurant patron Dawson Foust desperately trying to save Gilbert's life.

In his incident report he noted his conversation with the group of friends.

'They advised they thought he was playing a prank by not coming up immediately,' he wrote.

'Some members of the group did not realize Gilbert could not swim.

'It was later discovered the group was horse playing and one of the females in the group pushed Gilbert in the water, not knowing he could not swim.

'Foust advised me it was approximately 15 feet deep at the location he found Gilbert.'

Union Sheriff Dusty Gates gave a different account when he was interviewed about the April 14 incident.

'The party he was with began panicking or screaming and an individual within the restaurant saw what was going on and he came out and dove in and retrieved the victim,' he said.

'It was a joint effort by a lot of people to make this happen, and that's what we try to work for here in Union Parish, to work together to make it a better place.'

Gilbert remains on life-support in hospital as doctors try to establish whether he will ever recover.

'It's still a battle because we don't know what to expect,' his mother said.

'We don't know if it may turn worse again because at one point, he was off the ventilator but then they put him back on two days later.'