The four serving and former Mirror group journalists arrested yesterday have been widely identified as People editor James Scott, ex-Sunday Mirror chief Tina Weaver, former People editor Mark Thomas and People deputy editor Nick Buckley.
Detectives on Operation Weeting said they had “identified and are investigating a suspected conspiracy to intercept telephone voicemails at Mirror Group Newspapers”.
It is being treated as a separate conspiracy to the two being investigated at the now defunct News of the World newspaper and is believed it mainly concerned the Sunday Mirror newspaper in the years 2003 and 2004.
The four arrested journalists have now been bailed to return to their London police stations on various dates in April, according to the Met.
Weaver left the Sunday Mirror last May when publisher Trinity Mirror announced plans to move to a seven-day publishing operation.
She started her career at the South West News agency before joining the People in 1989 as a reporter. In 1993 she joined the Daily Mirror and a year later left for Today.
When the paper closed in 1995 she rejoined the Daily Mirror and became the paper's deputy editor in 1997.
Weaver was appointed editor of the Sunday Mirror in April 2001 when Colin Myler resigned following the collapse of the trial in which two Leeds soccer stars were accused of assault, when the paper was found to be in contempt of court.
Scott became editor of the People in June 2012 after Lloyd Embley was named editor-in-chief of Trinity’s national titles.
Before that he was deputy editor of the Sunday Mirror. He also started his career at South West News, before moving to The Sun.
He joined the Mirror in 1999, working as a showbiz reporter, before moving to The People as deputy news editor. He later moved to the Sunday Mirror as news editor and became deputy editor in 2004.
Buckley became deputy editor of the People in June 2012 .Before that he was Sunday Mirror head of content.
Thomas began his career as a reporter on the People in 1998 and moved to the News of the World in 1994. In 1997 he became features editor at the Daily Mirror and in 2001 became deputy editor.
Two years later he was appointed editor of the People. He left the paper in 2008 to work in PR.
On 4 July, last year, former Daily Mirror journalist Greig Box-Turnbull was arrested on 4 July on suspicion of corruption, conspiracy to commit bribery and conspiracy to cause misconduct in a public office.
On 11 July last year, Sunday Mirror crime correspondent Justin Penrose was arrested on suspicion of conspiracy to cause misconduct in a public office.
Both are still on police bail and neither have yet been charged with anything.
Lawyer Mark Lewis said in October that he was planning to sue Trinity Mirror over alleged phone-hacking involving four high-profile individuals: former England football manager Sven-Goran Eriksson, Coronation Street actress Shobna Gulati, Abbie Gibson (a former nanny for the Beckham family) and Garry Flitcroft (the former captain of Blackburn Rovers football team).
Trinity Mirror company secretary Paul Vickers said: "We note the arrests this morning of two current and two former journalists employed by the Group as a result of the Metropolitan Police Operation Weeting. The police are investigating allegations of phone hacking on the Sunday Mirror in the period 2003 and 2004.
"We take any allegation against employees very seriously and are co-operating with the police on this matter."
In a further statement Trinity Mirror said: "We can confirm that James Scott the editor of the People and his deputy, Nick Buckley, were arrested this morning as part of Operation Weeting. We understand that two former employees were also arrested this morning."