Aaron Hernandez -- I Didn't Shoot Murder Witness in the Face ... to Intimidate Him

Aaron Hernandez pled not guilty to witness intimidation -- denying that he shot his friend in the face to keep him from testifying in a double murder investigation.

According to the district attorney's office, Hernandez intimidated his friend Alexander Bradley -- who allegedly witnessed the tight-end shoot and kill Safiro Furtado and Daniel de Abreu in 2012 over a spilled drink.

Hernandez has pled not guilty to the murder charges.

The Suffolk County DA believes Hernandez was paranoid about cops watching him after the murders ... and shot Bradley while driving home from a club in Florida.

Bradley survived, but lost an eye in the shooting.

FYI ... looks like Hernandez got some new prison ink too... a star on his neck included with the word "lifetime."

Interesting choice -- given his life sentence for the murder of Odin Lloyd.