Public Broadcaster CBC said Senator Patrick Brazeau was in police custody and officers were searching his Ottawa area home, which had been taped off with yellow police ribbons.

A police spokesman confirmed they were holding a man for domestic violence but did not identify Brazeau nor the victim, saying their investigation was ongoing and no charges had been laid yet.

Prime Minister Stephen Harper meanwhile announced in the House of Commons Brazeau's departure from the ruling Conservative group.

"In light of the serious nature of the events reported today, I have removed Senator Brazeau from the Conservative caucus," Harper said.

Harper's office added that "the prime minister was appalled and saddened when he heard the allegations and took immediate action."

Harper named Brazeau to the senate in 2009.

Recently, the feisty, tattooed senator has come under fire for disparaging comments on social media about a female journalist and a native chief on a hunger strike.

The former head of the Congress of Aboriginal Peoples, a national organization representing natives who live off-reserves, he has also been a vocal critic of a recent aboriginal rights movement.

But his calls for greater fiscal accountability were drowned out by news this week of an investigation into his use of the address of his ex-wife's father to claim a tax exemption for those living on aboriginal reservations.

Last March, Brazeau fought now-Liberal leadership candidate Justin Trudeau, the son of former prime minister Pierre Trudeau, in a charity boxing match and lost.

He will now sit as an independent senator, according to CBC, although he may be booted from the senate if he is charged and convicted of a serious crime.