The suspect is thought to be involved in money laundering and perverting the course of justice.
The arrest is connected to a police investigation into the affairs of inspector Mohammed Razaq who was charged with insurance and mortgage fraud last May.
It is alleged that Razaq exaggerated insurance claims following flood damage at his house and secured a mortgage at a lower rate by failing to disclose he was buying to let.
He has denied the offences and is due to appear at Manchester Crown Court next month.
Razaq has been suspended from duty since his arrest.
He said he was unaware of the latest arrest in the case and declined to comment further while the case was ongoing.
A spokesman for Greater Manchester Police said: “A 49-year-old man has been arrested as part of an ongoing investigation into insurance fraud.
“The man, from Bolton, was arrested on Thursday, February 23, on suspicion of money laundering and perverting the course of justice.
“He has been released on bail pending further inquiries until April 19.”
