The hashtag #HelloBrother is gaining traction on Twitter following the massacre in Christchurch, New Zealand.

A man claiming to be a white supremacist was arrested Friday in connection with the shooting death of 49 people in two mosques.

The video of the shooting, which was apparently a livestream by the shooter, shows the first victim standing at the door of the mosque, greeting the gunman, saying the words “Hello, brother.” He was then shot to death.

Many tweets on Friday with the hashtag were accompanied by an image by an artist in Indonesia, illustrating the tragedy.