Five police officers may face action following the arrest of a university student who was left with a broken neck and in a vegetative state, the police watchdog has said.

The officers from Bedfordshire police are to be referred to the Crown Prosecution Service over whether they should face possible criminal charges, the Independent Police Complaints Commission said on Thursday.

An investigation by the police watchdog has also decided they may have a case to answer for discipline charges of gross misconduct.

The case concerns Julian Cole, who suffered a severed spinal cord after a night out in Bedford in May 2013 when he was aged 20. Cole, a student, was arrested by police outside a Bedford nightclub, and then carried to a police van.

The IPCC investigated six officers in total. It has decided that five officers may face gross misconduct disciplinary charges for failing in their responsibilities and duties. The IPCC also says that four officers it investigated may have a case to answer for “honesty and integrity” and that one officer may face a misconduct charge for use of force. One officer the IPCC investigated will face no action.

The officers are understood to deny any wrongdoing.

The IPCC deputy chair, Sarah Green, said: “This has been a complex and lengthy investigation involving examination of over 900 documents, interviews with witnesses, a number of medical expert opinions, CCTV trawls and forensic analysis.

“We are now satisfied we have gathered all the available evidence to enable the Crown Prosecution Service to determine whether or not charges should follow. We have kept Mr Cole’s family and Bedfordshire police updated on our progress.”

A referral to the CPS is made when the IPCC investigation indicates that a criminal offence may have been committed. It does not mean that criminal charges will necessarily follow. The CPS will decide whether charges should be brought, based on the test set out in the Code for Crown Prosecutors.

Cole’s case was first reported by the Guardian. His mother, Claudia Cole, said: “Following that night, he has been left paralysed and in a vegetative state and he will need 24-hour care for as long as he lives. Julian is still alive, but it cannot be said that he is really living. This year Julian was supposed to be graduating from Bedfordshire University with a degree in sports science, but he never got a chance to do that. Julian had big dreams, big ambitions, and all of those are dashed. We miss him so much every day.”

The family claim they were misled by an officer about details of the case after the incident in May 2013. They say one officer told them Cole was talking after his arrest, but this would be impossible with a severed spinal cord. Another allegedly said Cole was drunk. He had consumed alcohol, but tests showed he was under the drink-drive limit.

Claudia Cole added: “It has been the hardest three years waiting for the IPCC investigation to conclude. We want to see the report and all the evidence to learn the full truth of what happened. We also want to see justice for Julian – it will not bring him back, but we hope the CPS makes a swift decision on criminal prosecutions against the officers.”

The incident happened when Cole returned to Elements nightclub, in Bedford, to request a refund after he and friends were asked to leave. CCTV captured some of the incident, but not the moment when Cole apparently lost consciousness. He reappeared on CCTV handcuffed and being carried by officers into a police van.

One of the five officers referred to the CPS has since retired, Bedfordshire police said. The IPCC has asked the force to suspend the four officers still serving, but Bedfordshire police said they were on full duties.

Cole was arrested by police on suspicion of a public order offence, which was dropped because of the injuries he suffered.