The three-year-old boy hurled into a reptile pit by a man with special needs was bitten by a saltwater crocodile in front of his mother and her baby.

The child suffered a shattered arm and pelvis with CCTV showing the brutal attack at Old Hurst zoo in Cambridgeshire now handed to detectives.

The 30-year-old man arrested at the scene on suspicion of attempted murder was quickly bailed until September 18 after police said he 'was assessed as not being fit for interview'.

Carers accompanying the disabled man were reportedly 'on their phones' and 'ten metres behind him' when he picked up the boy, lifted him over a security fence and hurled him into the enclosure swarming with alligators and crocodiles.

Police are examining the CCTV footage today as they assess whether the suspect will be charged.

The three-year-old victim was bitten by at least one saltwater crocodile – the animal with the world's strongest bite – after landing in water containing around 50 reptiles, including some species that can weigh as much as a tonne and grow up to 22ft.

The zoo's co-owner, Tracey Johnson, jumped into the enclosure to save the little boy from the jaws of the crocodiles.

She was followed in by her husband, Andy, and one of their sons, Edward, on Thursday afternoon. The child is reported to have been visiting with his mother, who also had her baby with her on the zoo trip.

Their friend Chris Newman, director of the National Centre for Reptile Welfare, who has housed crocodiles at Old Hurst, said: 'We mustn't underestimate how much of a difference Tracey made.

'She was first in there. She jumped in and dealt with an awful situation. She was then joined by her husband and son. It was a team effort.'

The boy remains in a critical but stable condition in hospital.

The youngster is thought to have been tossed over the 4ft safety fence separating an aerial walkway from the enclosure below, where he landed on concrete before rolling into water.

Witnesses have spoken out about earlier seeing the man's carers 'on their phones' and not paying close attention during his outing to the zoo with other vulnerable adults.

A mother who was at the zoo at the time of the incident described hearing a 'loud scream' while sitting on a bench outside the enclosure.

She said: 'Someone later described the man that did it and said he was with carers.

'I don't know if it was definitely him, but I saw one bloke of a bigger build, he had two carers with him and they weren't paying him much attention.

'If it was him, his carers were maybe ten metres behind him. They were English and chatting among themselves and on their phones.'

On Friday, Cambridgeshire police confirmed the boy is still in a critical condition in hospital, with his injuries said to include a broken arm and pelvis.

A spokesman said: 'A three-year-old boy from Cambridgeshire remains in Addenbrooke's Hospital in a critical but stable condition.

'A 30-year-old man from Norfolk, arrested on suspicion of attempted murder, has been released on bail while detectives from the Major Crimes Unit conduct further enquiries regarding this incident. 

'The man, not known to the victim, was assessed as not being fit for interview.'

It is believed the man was on a trip with other vulnerable adults and had at least two carers with him. 

Yesterday, 55-year-old Mrs Johnson – whom one friend described yesterday as a 'special, steadfast, old-fashioned heroine' – was lauded as a hero after she climbed into the pen, waded to the boy and 'swooped down to pull him to safety'.

She is then thought to have escaped through a keepers' exit.

Chris Newman, director of the National Centre for Reptile Welfare, said: 'Her actions are nothing less than what I would expect of her. She is an incredible lady. It was a very brave thing to do.'

It was revealed on Friday that Mrs Johnson has just become a grandmother, with friends describing her as 'selfless' and 'always trying to help everyone'. 

Neither Mrs Johnson nor her husband, Andrew, are under any illusions about the dangers posed by the crocodiles, as experts warned yesterday that if the boy had fallen on or near one of the creatures they would have bitten him on instinct.

Mr Newman said: 'I wouldn't expect them to eat a child, but they would bite if it landed on or near them. That's where the danger lies – they have such a powerful bite. Even an investigatory bite would be catastrophic.' 

Speaking on an episode of Farmer's Weekly in 2011, Mr Johnson said: 'When we're handling the crocs, the main thing we use is a pig board, and the idea is if you're sitting like this, he'll grab your leg and drag you in. 

'And just having the board in front takes away the striking point, the grip point, and they don't bother.

'The best way to build trust with them is not to stand up and look like you're the dominant person, but to get down to their level and work with them.

'They seem to accept you as one of the group. They definitely identify us as a family different to anybody else that comes in.'

Witnesses said Mrs Johnson sprinted into the enclosure and pulled the injured child away from crocodiles to safety.

She and her shell-shocked husband were seen for the first time since the incident in exclusive pictures taken by the Daily Mail today as police sealed off the enclosure and spoke to staff. Friends said Mr and Mrs Johnson are 'mortified' by what happened.

Tearful witnesses described a blood-curdling scream from the reptile area at around 1.20pm on Thursday.

The boy had been on an elevated walkway watching at least 15 crocodiles and alligators when he was reportedly lifted over a 4ft safety fence and hurled about 15ft down into the enclosure.

According to multiple sources, the boy was attacked by at least one crocodile in the enclosure, which houses more than a dozen crocodiles and alligators, including two large Nile crocodiles, Romeo and Cuddles, which measure between 9ft and 11ft. Romeo, the male, can weigh up to 485lb.

A mother who was at the zoo at the time said: 'We saw the air ambulance come over within about ten minutes. They held up a white sheet in between the farm shop and the cafe so no one could see what was happening. 

'My daughter was oblivious. The little boy was only three and my daughter is two, it could have been her.' 

The Johnsons have said their 'thoughts and prayers are with the boy and his family'. 

Originating as a dairy farm, Johnsons has a butchers, farm shop, tea room and steak house, as well as the zoo. According to a blog post on its website, the crocodiles were initially kept to help dispose of waste meat from the butchery, but they went on to be the start of a zoo, which is now home to more than 100 animals, including lions, tigers, sloth bears, capybaras and meerkats.