Vincent D. Young, 32, was found hanging by a bed sheet at 7:10 p.m. by guards. His 33rd birthday would have been Saturday.
The Institute of Forensic Sciences will determine the cause of Young's death, which will be investigated by the homicide unit of the sheriff's department, the inspector general and the department's internal affairs unit.
Sheriff's office spokesman Ryan Sullivan said Young had been booked into jail on February 7, and was in the infirmary for detoxification. Young was in a single holding cell when deputies discovered him, and had not indicated any suicidal tendencies on his intake forms.
Sullivan said investigators have yet to determine how long Young was alone before deputies discovered him, but said state law requires prison guards to conduct rounds every 30 minutes.
"We usually do them faster," Sullivan added.
Young had an extensive criminal history in Harris County dating back to 2002, when he was just 18. Young had 12 misdemeanor and three felony convictions for offenses including drug possession, assault, forgery and deadly conduct, the latter for pointing a gun at someone.
Young was last arrested in December after he attempted to flee from a Houston police officer. At the time of his death, he faced charges of evading arrest, being a felon in possession of a handgun and drug possession, all felonies.
Between 2005 and 2015, 199 people died in custody of the Harris County Sheriff's Office. Most died from natural causes, though 26 committed suicide and 22 were killed by deputies.