Seven North Carolina prison workers have lost their jobs after an inmate died during a transfer to Raleigh’s Central Prison last month.

As of Tuesday, N.C. Department of Public Safety officials say five workers were fired and two resigned after the death of Michael Anthony Kerr, a 53-year-old Sampson County man with a history of mental illness who had been held in solitary confinement for more than a month prior to his death on March 12.

The seven who lost their jobs include 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 internal investigation. No criminal charges have been filed against the workers.

DPS officials announced an internal investigation into the unexplained death after the INDY’s questioning last month, later announcing additional plans for independent investigations by the N.C. State Bureau of Investigation and Disability Rights N.C., a nonprofit watchdog for individuals with disabilities.

Kerr, a U.S. Army veteran, had been sentenced to a term of more than 30 years for numerous convictions, including assault on a female, larceny and breaking and entering. Family members say he suffered a nervous breakdown after the death of two sons.

At the time of his death, Kerr was being transferred from Alexander Correctional Institution in Taylorsville to Central Prison, which serves as the state prison system’s primary medical and mental health center for male inmates.

Kerr family members have blamed prison officials for his death, indicating his mental health had been deteriorating inside his isolated cell at Alexander Correctional. Family members who viewed his body also said he appeared to have been beaten and starved.

Officials are awaiting the autopsy results from the N.C. Office of the Chief Medical Examiner, which could take months to complete.

“I think he died in that hole,” his wife, Katrenia Robinson of Fayetteville, told the INDY.

Meanwhile, the department’s second-in-command, Chief Operating Officer Ellis Boyle, resigned abruptly last week, although DPS spokeswoman Pam Walker says Boyle’s departure is unrelated to the investigation. DPS also was under scrutiny last week after it was learned some crime victims’ personal information had been available online.

Prison officials in North Carolina and nationwide have been under pressure to eschew solitary confinement, a practice typically used to segregate prisoners with severe mental illness or inmates who have broken prison rules. Critics say solitary confinement can worsen mental illness or even create it in inmates with no history of mental illness.

A 2011 internal report drew particular attention to Central Prison, with accounts of mentally ill inmates left unmedicated and ignored in squalid cells.