The 24-year-old suspect, who has not yet been publicly named, confronted the victim — identified by sources as Jordan Neely — who had started an aggressive rant Monday afternoon while traveling on a northbound F train, according to the New York Post.

The unnamed straphanger, who sources say is a Marine veteran, then moved behind Neely before wrestling him to the ground in a stranglehold.

Vazquez says the man kept Neely in the choke for upwards of 15 minutes, the Post reports.

Neely, who has a history of mental health issues and was living on the streets at the time of the incident, quickly lost consciousness while in the chokehold.

The hold was so tight that EMS workers were unable to revive him, according to police and law enforcement sources said.

The man who choked Neely was taken into custody before being released later on without any charges, per the New York Post.