A man arrested on suspicion of attempted murder after a three-year-old boy was allegedly thrown into the crocodile enclosure at a zoo has been released on bail.Cambridgeshire police said the 30-year-old man from Norfolk was assessed as not being fit for interview by officers and has been bailed while detectives from the major crimes unit conduct further inquiries.A three-year-old boy from Cambridgeshire remains in Addenbrooke’s Hospital in a critical but stable condition.Emergency services were called to Johnson’s of Old Hurst zoo in Huntingdonshire after 1pm following reports that a three-year-old boy had suffered serious injuries after falling into the enclosure.He was pulled out by staff from the zoo and received medical treatment at the scene before being taken to hospital, police said.The incident happened at the crocodile enclosure (Johnson's of Old Hurst)Locals told The Sun and the Press Association that Tracey Johnson, the wife of the zoo’s owner, jumped in to the enclosure to save the three-year-old boy but the family has not commented on what happened.Chris Newman, the director of the national reptile centre who has housed crocodiles at the zoo and knows Ms Johnson “very well”, told BBC Radio 4’s Today programme that her actions should be recognised as “incredibly heroic”.“Frankly it's nothing short [of what] I would expect of her, that's exactly what she would do. She's a very brave, very strong lady,” he said. “I don't know which enclosure it was, but I mean it's about a 15 ft drop, so for her to get into their that quickly and save the child is, you know... just a remarkable act of bravery.”The 30-year-old man is on bail until 18 September, police said.Cambridgeshire police’s major crime unit is currently investigating the incident (PA Wire)Det Insp Verity McCann said: “Our enquiries are ongoing as we continue to understand the circumstances surrounding this distressing incident.“Our thoughts remain with the boy, and his family and specialist officers continue to support them through this difficult time.”Following the incident, Johnson’s put out a statement on their social media to say that the tropical house - home to the crocodiles - would remain closed until further notice “out of respect to the family”.They added: “Our thoughts and prayers are with the boy and his family following the incident that occurred today.”Johnson’s of Old Hurst houses more than 100 animals, but specialises in the conservation of crocodiles. Andy Johnson, owner of the zoo, participated in composing a European-published dossier on the farming, welfare and husbandry of crocodilians, according to the website.Mr Newman said that the zoo was “incredibly well run” and “the zoo licencing act is very stringent.”