Former Karnataka Food and Civil Supplies Minister H Halappa was arrested on Sunday in connection with a rape case filed against him by his friend's wife.
Halappa, who appeared before the CID today following a notice served by the investigating agency on May 6, was questioned for three to four hours, CID DIG Charan Reddy told PTI.
"We have formally arrested him after interrogating him. Halappa has however denied the allegation," he said.
The former minister was later taken to a local hospital for a medical test, police said.
The police on May 6 had pasted a notice at two of Halappa's residences asking him to appear before it by May 10.
Halappa had quit his post as minister after a media report claimed he had sexually assaulted his friend's wife at their residence in November last at Shimoga, Chief Minister B S Yeddyurappa's home district.
He had moved the court in Shimoga, seeking anticipatory bail, which has been posted for hearing to May 11.
Chandravathi, wife of financier Venkatesh Murthy, had filed an FIR claiming Halappa had raped her and later threatened the couple with dire consequences if they spoke about it.
Police have booked charges of criminal intimidation, wrongful confinement and restraint against Halappa and two of his aides.
Halappa has denied all the charges, calling it a political ploy by his adversaries. The opposition had raised a hue and cry over the issue and demanded a CBI probe.