Three South Yorkshire MPs are under investigation over allegations of electoral expenses fraud.
It is claimed that Labour MPs Sir Kevin Barron, Sarah Champion and John Healey failed to declare thousands of pounds spent on recruiting staff to get them re-elected last year.
The three MPs all deny the claim.
A South Yorkshire Police spokeswoman said: "South Yorkshire Police is investigating allegations of electoral expenses fraud in Rotherham in 2015.
"The investigation remains ongoing and an application for an extension has been granted by the courts."
Rother Valley MP, Sir Kevin, said: "All my elections expenses were declared within the law and the rules set out by the Electoral Commission."
Mr Healey, who represents Wentworth and Dearne, said: "These allegations are simply wrong. My expenses for the 2015 general election were reported fully in accordance with the law and the rules set out by the Electoral Commission."
And Rotherham MP, Ms Champion, said: “All my elections expenses are declared within the law and the rules set out by the Electoral Commission and IPSA.”