The British National Party's candidate for mayor of Liverpool has been arrested on suspicion faking signatures on his nomination papers.
Mike Whitby, who is on Thursday's ballot paper for the directly-elected post, was held by police at his home in north Wales on Monday.
Detectives arrived at the house at 7.30am but the candidate refused to co-operate and officer were unable to detain him until around six hours later, the Press Association reported.
Merseyside Police said he remains in custody being questioned over alleged electoral fraud by making false statements and faking signatures on nomination election papers.
Detective Superintendent Martin Andrew, of Merseyside Police, said: "Following an allegation that nomination forms for the mayoral elections had been fraudulently filled in, a police investigation was launched.
"Officers conducted extensive inquiries in the Wavertree area of Liverpool over the weekend and interviewed a significant number of people.
"Following those inquiries and after taking advice from the Crown Prosecution Service, Merseyside police officers attended an address in the Wrexham area of North Wales at 7.30am today to speak to the homeowner about the allegations.
"My officers made repeated attempts to speak to the occupant and, at around 1.30pm today, they arrested a 59-year-old man on suspicion of making false statements and faking signatures on nomination election papers - an offence under Section 65A of the Representation of the People Act.
"The man was taken to a police station in Wrexham where he was interviewed about the allegations.
"He currently remains in police custody."
The complaint was made to Merseyside Police following an investigation by the Liverpool Echo which reported alleged irregularities in Mr Whitby's nomination papers.
A BNP spokesman said Whitby denies the allegations and stands by the names on his nomination form.
He added: "Mike and his wife went to every single one of those people and explained who he was and what he stands for.
"What we have here is a newspaper trying to scupper an election campaign."
There are a total of 12 candidates for mayor in Liverpool this Thursday, including Labour leader Joe Anderson and Liberal Democrat Richard Kemp.
Tony Caldeira is the Conservative candidate. Steve Radford from the Liberal Party and John Coyne for the Green Party are also standing.