Stoneman Douglas Shooter Nikolas Cruz Attacks Jail Guard, Caught on Video

Nikolas Cruz -- the gunman responsible for killing 17 at Marjory Stoneman Douglas High School -- is facing new charges for attacking a jail guard ... and the video showing the whole thing go down is chilling.

Cruz was captured on surveillance video, released in court Wednesday, in an all-out brawl with a Broward County Jail guard. Just before the attack, which happened in 2018 -- but is just now coming to light -- Cruz can be seen walking in circles with his head down.

Cruz and the guard then appear to exchange words ... the guard said in court he told Cruz not to drag his feet so he wouldn't ruin his jail-issued sandals. Cruz appears to flip him off with both hands and then charges at him. They wrestle for a bit before Cruz throws some heymakers.

Eventually, the guard takes control, after pulling out his taser, and Cruz gets on the ground and taken into custody. It does not appear the stun gun was deployed.

Cruz was was hit with battery and assault charges from the incident. The jail altercation is reportedly being tried separately from his ongoing first-degree murder case.

Cruz's attorneys say the jail guard mistreated Cruz and that he provoked the attack.