The Jefferson County Sheriff's Office is investigating the death of a 33-year-old man who was in the process of being booked into jail when he passed out and died, Saturday.

Deputies say Byron James Sessions, 33, of Nederland, was arrested by Port Arthur police officers on a criminal trespassing charge around 9 a.m.

Investigators say as officers escorted him to the jail, Sessions passed out. Medical personnel started CPR and Acadian ambulance also responded.

Sessions was pronounced dead at 10:15 a.m. An autopsy has been ordered.

The District Attorney's office, Jefferson County internal affairs, Port Arthur police and the Jefferson County Sheriff's Office are all involved in the investigation.

Sheriff Stephens says no altercation happened prior to Sessions passing out.