LogFAQs > #976691187

Belgian here, got some more details from local news. They don't mention the video taking credit yet though.

According to video taken by residents of the neighborhood some guy in an orange coat and white helmet pulled up on a scooter and started firing an automatic weapon.
The victims fled into a nearby apartment building, only for him to follow and open fire in the lobby.
One of the victims tried to escape the lobby and was gunned down. The shooter headed towards the exit, yet turned around to fire one more time on the victim that was already on the ground. Video shows him getting on the scooter and leaving

https://www.tijd.be/politiek-economie/belgie/brussel/twee-doden-bij-schietpartij-met-oorlogswapen-in-brussel/10499674.html

EDIT: Other news sites do mention the video and also the fact that he shot 3 people, but the 3rd victim is still alive. And they also say the man in the video claiming to be the shooter looks similar to the shooter in the footage captured by bystanders