N.C. Department of Public Safety officials say that the resignation of agency Chief Operating Officer Ellis Boyle is unrelated to the ongoing investigation into the unexpected death of an inmate last month.

DPS issued a release Wednesday announcing Boyle’s replacement, but did not explain why the agency chief was leaving. It comes as the department has fired five workers and accepted the resignation of two workers related to the death of inmate Michael Anthony Kerr, a prisoner who died March 12 en route to Raleigh’s Central Prison.

Kerr, a Sampson County native with a history of mental illness, spent more than a month in isolation at Alexander Correctional Institution in Taylorsville prior to his death. Family members have blamed prison officials for his death. Meanwhile, officials await the results of a medical examiner’s report expected to explain Kerr’s cause of death.

According to DPS, the fired prison workers were nurses Brenda Sigman, Wanda St. Clair and Kimberly Towery; nurse supervisor Jacqueline Clark and captain Shawn Blackburn. Nurse Lisa Kemp and staff psychologist Christine Butler have also resigned during the course of the investigation.

More as it develops.