Sergio Brown has been transported from San Diego to Illinois ... where he's now set to go in front of a judge on Wednesday to face two separate charges in connection with his mother's death -- first-degree murder and concealment of a dead body.
The Maywood Police Department said in a statement to TMZ Sports late Tuesday evening the hearing will begin at 9 AM CT at a Maywood courthouse -- several miles from where Brown allegedly killed his 73-year-old mom and dumped her body near a creek behind her home.
Police released Brown's latest mug shot in announcing the updated charges against the former football player ... and, according to a spokesperson for the Maywood Police Dept., he was wearing a Ben Roethlisberger jersey as he was being processed.
Brown had been behind bars in Southern California since Oct. 10 ... after authorities pulled him out of Mexico -- where he was spotted dancing and partying in the days following his mom's passing.
Video shot from inside of a plane just after Mexican officers apprehended Brown showed he was very uncooperative as they tried to extradite him back to the U.S.
It's unclear if law enforcement faced any sort of similar issues while transporting him from SD to Illinois this week.