The Florida Department of Corrections is investigating the in-custody death of a 48-year-old Palatka man serving life in prison for a pair of 2016 murders. Jerry Keene Jr. was found dead Sept. 26 at Wakulla Correctional Institution in Crawfordsville, according to the Department of Corrections. “The safe and secure operation of Florida’s correctional institutions is the Department of Corrections' top priority,” the agency said Wednesday in an emailed statement. The 48-year-old was convicted of first-degree murder in the death of 44-year-old Thomas Lombardo, who was killed during an argument in January 2016. While in custody on charges in that case, Keene beat his cellmate Austin Steybe, a 20-year-old man awaiting trial in the murder of his own grandmother.