The man who said he had a bomb and locked himself in a Papakura service station is the brother of a Northland man whose death more than a decade ago prompted claims of police negligence.

Gregory Thomas Nigro is facing five charges in connection with the siege, which forced the evacuation of hundreds of businesses and shoppers on Wednesday.

Nigro, 52, told service station workers he was protesting against police and claimed they had killed his brother.

He spent more than five hours inside, refusing to speak to police until he was flushed out by teargas. He was not carrying a bomb.

His brother, Peter Nigro, died in October 1992, and it is the second time in recent years that the death has been publicly highlighted in a dramatic way.

In 2003, a person scaled the Auckland Harbour Bridge and wrote "Pigs kill Peter Nigro" in large red letters.

A coroner found that Mr Nigro, 38, most likely drowned after a boating accident.

His widow, Caryn, who still lives at their home in Taupo Bay, 40km northeast of Kaitaia, has always maintained that the events surrounding her husband's death were suspicious and the inquest was flawed.

An autopsy was not carried out and the only surviving witness was not present at the inquest.

Mr Nigro was fishing with a local resident, Murray Sharpe, in a 4.9m wooden runabout when it broke up on the afternoon of October 13.

They had tied themselves to floating fuel tanks and although Mr Sharpe, a poor swimmer, made it to shore Mr Nigro - a lifetime surfer - did not.

Mr Sharpe raised the alarm about 8.30pm after making it to shore but police determined the conditions were not suitable for a night search.

Mrs Nigro said friends and family members launched their own search and found her husband's body 3km from shore at 8.25am the next day.

She said a night search should have gone ahead: there was a full moon, conditions were not as bad as police made out and the estimated time of death was as late as 4am.

An inquest held a month after Mr Nigro's death vindicated the police decision that a night search was unsafe.

Mrs Nigro said she had photographs showing extensive bruising to her husband's body but that was never explained. An inquiry into the police handling of the case for the Police Complaints Authority in 1999 found no neglect of duty.

Mrs Nigro said she had not seen Greg Nigro since her husband's funeral more than 12 years ago.

She was upset to learn he was charged over the drama at Papakura and expressed her concern at the impact on the community.

Mrs Nigro said there was "no justification" for his actions.

"I think what he did was shocking but it just shows you how much pain there still is in the loss of Peter. I feel sad to think that Greg has felt he has been pushed to the limit, to endanger so many people before someone would listen to him."