Ex-UFC Star Diego Sanchez Arrested, Allegedly Fired Gun From Moving Vehicle

1:15 PM PT -- Sanchez appeared before a judge minutes ago ... who said he will be kept in custody after the state filed a motion for preventive detention. His case is being sent to district court, where it will be decided if he stays locked up or is released pending his trial.

Diego Sanchez -- the winner of the first season of "The Ultimate Fighter" -- was arrested Thursday in New Mexico ... after he allegedly fired a gun while passing by a crash, TMZ Sports has confirmed.

According to court documents, officers were working an incident on I-40 in Albuquerque when they say a passenger in a Jeep Gladiator -- later identified as Sanchez -- shot off a round as the vehicle drove by the scene.

Cops then followed the car and pulled it over a short time later. While officers say he admitted there was a gun in the car ... Sanchez denied ever firing a shot.

The driver of the vehicle -- who is not facing any charges -- told cops Diego did, in fact, shoot a gun out the car window and even laughed about it.

After searching the car, cops say they found three rounds on the passenger side and the weapon in the back pocket of the driver's seat.

The 43-year-old is currently behind bars and facing two charges -- one count of shooting at or from a motor vehicle and negligent use of a deadly weapon

Sanchez last fought for the UFC in 2020, losing via unanimous decision to Jake Matthews. His last MMA fight took place in 2022, ending in a unanimous decision loss to Kevin Lee.

Over his nearly two-decade-long career, he compiled a record of 31-14. He fought for UFC gold once against B.J. Penn, but was knocked out in the fifth round.