A murder inmate serving a life sentence died in an Alabama prison Wednesday after “exhibiting erratic behavior,” the state Department of Corrections said Thursday.

DeMarcus McCloud, 45, entered the Limestone Correctional Facility’s dining hall “exhibiting erratic behavior and had to be subdued by officers,” ADOC said.

McCloud, who committed murder in Calhoun County, was taken to the prison’s health care unit for an assessment.

After the assessment, McCloud became unresponsive, the agency said.

Life-saving measures were attempted but unsuccessful.

McCloud was declared dead by an attending physician at the prison.

The inmate’s death was being investigated by ADOC, and a cause of death is pending an autopsy and the conclusion of the probe.