Driver Who Plowed Into Charlottesville Counterprotesters Identified, Charged with Murder (UPDATE)

5:22 PM PT -- An Army spokesperson tells TMZ ... James Alex Fields Jr. was enlisted in the Army in 2015, and reported to basic military training in August of that year. He was released from active duty 4 months later due to a failure to meet training standards.

The alleged driver of the car that plowed into a group of counterprotesters in Charlottesville has been charged with one count of second-degree murder ... TMZ has learned.

The suspect's been identified as James Alex Fields Jr., a 20-year-old Ohio man. He's facing the second-degree murder charge, along with three counts of malicious wounding and one count of failing to stop at an accident that resulted in death ... according to the superintendent of the Albemarle Regional Jail.

In disturbing video of the crash ... the suspect Fields appears to deliberately drive his Dodge Challenger into a group of counterprotesters walking down the street, then floors it in reverse in an attempt to flee. He was captured shortly after.

As we reported ... a 32-year-old woman was killed in the incident. The city's police chief said at least 35 people were injured during Saturday's violence between white nationalist rallygoers and counterprotesters.