Liverpool mayor Joe Anderson has been released on bail after being arrested by police investigating claims of bribery and witness intimidation.
He was held with four other people as part of an investigation into the awarding of building contracts.
It is understood the Labour Party has suspended Mr Anderson pending the outcome of the case.
Merseyside Police said all five people “have been released on condition bail, pending further inquiries.”
Their year-long investigation, Operation Aloft, has focused on a number of property developers.
On Friday, Mr Anderson, 62, was arrested on suspicion of conspiracy to commit bribery and witness intimidation.
Police said they detained two other men, from Liverpool and Ainsdale, for the same offences.
Two more, aged 25 and 72, were arrested on suspicion of witness intimidation.
Liverpool City Council said it was co-operating with Merseyside Police.
Father-of-four Mr Anderson, an ex-social worker and former member of the Merchant Navy, joined the Labour Party in 1980.
He was elected mayor of Liverpool in 2012, having been on the city’s council since 1998.
In 2016, he vied to become Labour’s candidate for the Liverpool City Region mayoral post, but was beaten by then Walton MP Steve Rotheram, who currently holds the position.
Mr Anderson recently spearheaded the drive for mass coronavirus testing in Liverpool.
His brother Bill died in October after contracting the virus.