(KAIR)--Natural causes are named as the likely cause of death for a 70-year-old Jackson County Jail inmate, found unresponsive in his cell early Tuesday morning.

According to a release from the Kansas Bureau of Investigation, an autopsy for Mark Hull was conducted Wednesday, with the preliminary results indicating “his manner of death was natural, and likely related to heart complications,” with no foul play suspected. The final autopsy report remains pending.

Jail employees, the release explains, discovered Hull unresponsive shortly before 3:00 Tuesday morning, and “life-saving measures were attempted and [Jackson County] EMS was contacted. When they arrived, they took over attempts to revive Hull, attempts that were unsuccessful, with Hull pronounced dead at 3:40 that morning.

As required by state statute, the KBI was contacted by the Jackson County Sheriff- Office to oversee the investigation, which is ongoing.

Hull was a resident of Topeka.