An investigation has been launched in Fargo after a jail inmate was hospitalized after they became unresponsive.

The incident happened at the Cass County Jail, with the sheriff's office saying the inmate was taken to a local hospital for treatment.

"It is believed that the inmate ingested a controlled substance," the Cass County Sheriff's Office said.

The inmate has since been released and returned to the jail, but the sheriff's office and the North Dakota Bureau of Criminal Investigation have launched a probe.

They're seeking to determine how the substance was introduced to the facility, and how the inmate obtained it.