Sellner, originally from Austria, is the leader of a pan-European far-right group called Generation Identity. Pettibone, Sellner's girlfriend, is a YouTuber from the US.
Sellner made headlines last summer when his group took a small boat out into the Mediterranean Sea and proceeded to shoot flares at a ship called the Aquarius, a 250-foot-long vessel operated by a charity called SOS Méditerranée and Médecins Sans Frontières (also known as Doctors Without Borders).
The group was briefly detained by Italian police after the stunt, which was meant to push a conspiracy theory that nongovernmental organizations like MSF aren’t actually saving refugees at sea, but are part of an illegal human trafficking operation.
Sellner, Pettibone, and a Canadian YouTuber named Lauren Southern spent several weeks in Catania, Italy, attempting to disrupt ships trying to rescue refugees lost at sea. The whole episode ended with Sellner's boat being stranded in the water, unable to find a port that would take it. The group had to be rescued by one of the NGOs they were trying to impede.