BERLIN (AP) — Austrian authorities have searched the home of a prominent far-right activist as part of a probe into his ties to the alleged Christchurch mosque gunman, officials said Tuesday.

Martin Sellner, head of the white nationalist group Identitarian Movement of Austria, said on social media that police searched his apartment Monday and seized electronic devices after he received a "disproportionately high donation" from a person named Tarrant — the same surname as the suspected Christchurch shooter.

Christoph Poelzl, spokesman for Austria's Interior Ministry, confirmed Tuesday that the country's BVT domestic intelligence agency searched the premises in Vienna at the request of prosecutors in the city of Graz.

Hansjoerg Bacher, a spokesman for Graz prosecutors, said prosecutors had stumbled across the donation as part of an existing probe against Sellner into possible financial offenses.

"The purpose of the investigation is to examine links between Mr. Sellner and the Christchurch attacker," Bacher told The Associated Press.

He declined to confirm when the donation took place, but said it was much higher than other contributions made to Sellner or his Identitarian Movement.

"Most donations were in the area of two-to-three figures, whereas this donation was in the low four-figure area," Bacher told The AP. "This made it stand out, and the events in New Zealand put a face to this donation."

He said the investigation against Sellner is based on Austrian anti-terror laws.

"We need to determine whether there is a connection and if so, whether it's criminally significant," said Bacher.

Sellner denied having anything to do with the March 15 massacre, in which 50 Muslims were killed in the southern New Zealand city.

Australian Brenton Tarrant was arrested within an hour of the mosque shootings and has been charged with murder.

"I had nothing to do with the attack," Sellner said in a video statement posted on YouTube, adding that he would donate the money to a charitable organization.

He suggested the reason for the donation might have been to provoke repressive measures against "patriots."

Austrian authorities said last week that the Christchurch shooter visited Austria, but declined to confirm when or whether he met with any far-right activists during his trip.

Some of Tarrant's anti-Muslim views are echoed by the Identitarian Movement. The group is close to sections of the nationalist Freedom Party, which is part of the country's coalition government.