A former Norwich police officer and his wife, a serving Norfolk police officer, have been arrested again as part of an ongoing fraud investigation, it has emerged.

Detectives from the Eastern Region Specialist Operations Unit (ERSOU) arrested three men and a woman on Wednesday morning on suspicion of fraud offences in connection with the ongoing inquiry.

Ex-policeman Ben Staff and his wife, Catriona, who is a serving PC with Norfolk Constabulary, are understood to be two of the four people arrested in the latest swoop by officers.

Mr Staff, who quit the force in 2008, and Mrs Staff were both previously arrested as part of the inquiry in February on suspicion of fraud and money laundering offences while Mr Staff was further arrested on suspicion of blackmail in March, when he was questioned and released on bail.

The couple, both in their 30s, have been released on police bail pending further inquiries.

Also arrested on Wednesday were two men in their 20s, one of whom has also been previously arrested.

They too have been released on bail pending further inquiries.

The latest police action brings to seven the total number of people arrested as part of the investigation.

As reported in June, a 65-year-old man from Norwich and a 29-year-old man from Newcastle were both detained on suspicion of money laundering and later released on police bail while the inquiry continues.

A man in his 40s was arrested at an address in Norwich in March on suspicion of blackmail and has since been released on bail pending further inquiries.

And a woman, in her 50s, was arrested in Norwich, in February, by detectives from ERSOU on suspicion of alleged fraud offences and has been released on bail pending further inquiries.

Norfolk Constabulary previously issued a statement which revealed the Norfolk police constable had been suspended from duty until the outcome of the criminal investigation and that the matter had been referred – as was routine – to the Independent Police Complaints Commission (IPCC).

Have you got a crime story? Email Norwich Evening News crime correspondent peter.walsh@archant.co.uk