The Oklahoma State Bureau of Investigation said Friday that it is investigating an in-custody death at the jail in Lawton.
The death happened around Thursday afternoon. The Lawton Police Department requested OSBI's help Friday.
Authorities said the man, who was 30 years old, was arrested around 1 a.m. Thursday on two city warrants and booked into the jail.
The man was found unresponsive around 4 p.m. OSBI said life-saving measures were attempted by jail staff, but they were unsuccessful.
The man has not been identified, pending next-of-kin notification.