An innocent man who had his arm badly broken in a Victoria police raid at an LGBTI bookshop in Fitzroy last year says he is frustrated by the state’s anti-corruption watchdog finding the officer’s actions in restraining him were not disproportionate.

In May last year, Victoria police officers stormed the garage of the home attached to Hares and Hyenas in the Melbourne suburb of Fitzroy at 2am.

The bookstore is owned by Rowland Thomson and Crusader Hills. Nik Dimopoulos ran from the building when members of the Critical Incident Response Team entered the premises, fearing the police were intruders. Police mistook Dimopoulos for a suspect they were pursuing in relation to a car jacking and home invasion.

After a year-long investigation, Victoria’s Independent Broad-based Anti-corruption Commission (Ibac) found that, while Dimopoulos’s human rights were impacted when officers did not advise them of the reason of his arrest, his rights, or officially release him from custody, the use of force, which seriously injured his right shoulder, was proportionate.

“Ibac’s Operation Lynd has found Victoria police officers had reasonable grounds to enter and search the premises in Fitzroy given the nature of the offences suspected to have been committed and the information available to the officers at the time,” the Ibac commissioner, Robert Redlich, said.

“Ibac found the force used by police in restraining Mr Dimopoulos was not disproportionate to the officers’ objective of arresting Mr Dimopoulos, as the police involved reasonably believed such force was necessary to arrest a person who was struggling with police.”

Dimopoulos has maintained that police did not announce themselves at the raid, and Ibac made no finding on this point.

“[It was] the biggest stuff up I feel that they did not address themselves. Everything from that point, including the injury, the way they handled me, what it escalated to, all came from the fact at the entry point [the police] didn’t address who they were,” he said.

“For me it is the most fundamental part of what I experienced, and what amounted to the traumatic incident. It’s not what I experienced. It doesn’t at all reflect my experience,” Dimopoulos said.

It is understood bodyworn cameras were not in use for the raid, which could have provided more evidence on this point.

Victoria police’s professional standards assistant commissioner, Russell Barrett, said there were “no winners in this situation”.

“We have a man who was involved in a highly distressing situation and was injured during the arrest. We have already apologised for the emotional and physical impact this incident had on the man and will continue to offer him and his community our full support,” Barrett said.

“For someone to be injured during an interaction with police is not the outcome our members want or expect when they start their shift. That is why we apologised to the man so early on and we would do the same thing if we had our time over.”

Barrett said the findings that the actions were not racially or sexually motivated were welcomed by Victoria police.

Dimopoulos’s lawyer, Jeremy King, says his client will be pursuing the matter with the director of public prosecutions and will prepare cases for civil litigation.

Separate to this, Ibac has asked the Victoria police chief commissioner to report back in June on issues surrounding the CIRT’s use of force, equipment management records, body-worn camera use, and other policies and procures.

A year later, Dimopoulos says he still can’t look at his arm, and he needs to do physiotherapy and massages daily in order to stop it stiffening up and causing pain.

“This whole social distancing thing has pretty much been me for the past year,” he said.

“To this day, I still can’t look at my arm, it’s still too triggering, so it’s physical and still psychological. For this to come out today brings it all back.”