Danny Trejo July 4th Brawl Being Investigated As Hate Crime

Danny Trejo 's infamous Fourth of July brawl is now with authorities as cops investigate it as a potential hate crime -- especially after the actor claimed he and his buddy were targeted because of their race.

LAPD sources tell TMZ a battery/hate crimes report has been filed to investigate the incident at the Sunland-Tujunga parade last week ... and authorities are aiming to get to the bottom of what happened.

We're told when cops arrived on scene, most people involved had already booked it ... and those who remained didn't want to lodge a complaint.

But with punches clearly thrown and a full-out violent brawl all captured on camera and going viral online, cops apparently have enough to open an investigation.

Now we're told detectives will investigate to determine if any hate crime laws were violated -- and if they find evidence of such crimes, the case will be forwarded to prosecutors.

You'll recall ... Danny told us he's convinced race was a factor ... claiming he and his friend were singled out and targeted by water balloons while nobody else was.

His friend even gave us a glimpse of the aftermath -- showing off a bruised eye and arms.