Former Mirror reporter Greig Box-Turnbull held in bribery investigation

Prison officer and woman are also arrested by Operation Elveden police

Trinity Mirror, Britain's second biggest newspaper group, was drawn into the newspaper corruption scandal yesterday with the arrest of a long-serving Daily Mirror reporter.

Greig Box-Turnbull, 37, who left the million-selling tabloid in March after eight years, was arrested at dawn at his home in south London yesterday on suspicion of conspiracy to commit bribery and cause misconduct in a public office.

A 45-year-old male prison officer and 50-year-old woman were also detained at their homes in London and Kent. All three were questioned at police stations in London.

So far 37 people have been arrested by Scotland Yard's investigation into press bribery of public officials, Operation Elveden, which is running alongside operations Weeting into phone hacking and Tuleta into computer hacking. Until now, however, all the journalists arrested have been current or former employees of titles owned by News International, the UK newspaper arm of Rupert Murdoch's News Corp conglomerate.

The Metropolitan Police did not say the latest raids – which took place between 6am and 8am – had been prompted by information received from News Corp's management and standards committee, indicating that its inquiries into press misconduct are spreading deeper into the industry.

Trinity Mirror, which announced an ethical review of editorial practices at the height of the phone hacking scandal last July, made no comment on yesterday's arrests. However, Westminster City Council confirmed that Mr Box-Turnbull, who joined it in April as a senior media officer and is currently seconded to Richmond Borough Council, had been detained.

A spokesman for Westminster council said. "We are obviously aware of the arrest but we have yet to speak to the individual involved. In view of that and the possibility of legal action it would clearly be inappropriate for us to comment further."

Mr Box-Turnbull joined the Daily Mirror in 2004 and, according to the paper's website, specialised in home affairs, crime, investigations, campaigns and human interest stories. Although he left the paper on 15 March, he has continued to write stories for it, including a feature on Chatsworth stately home published on Mirror.co.uk yesterday.

His arrest comes at a particularly turbulent time for Trinity Mirror, which like most newspaper groups is suffering from falling circulations and advertising revenue at its 130 regional and national titles and in May ousted its chief executive Sly Bailey and the editors of the Mirror and Sunday Mirror, Richard Wallace and Tina Weaver.

At the Leveson Inquiry in May, the BBC's Jeremy Paxman claimed that Piers Morgan, editor of the Mirror between 1995 and 2004, instructed him how to hack a phone at a lunch in the Mirror's boardroom in 2002. But so far the £740m-a-year public-quoted company has avoided any firm link to the law-breaking which closed the News of the World and has damaged the reputation of The Sun, several of whose staff have been arrested on suspicion of bribing police.

Mr Box-Turnbull, who describes himself on his Twitter profile as an avid Oxford United fan and whisky-drinker, was arrested at his home in Morden, south London.

The Met Police said: "Following extensive inquiries carried out by officers from Operation Elveden... three people have been arrested."