COLUMBUS, OHIO (WTVN) -- Ohio Department of Rehabilitation and Corrections will do a separate investigation into the suicide of Ariel Castro.

Ariel Castro was found hanged in his cell at the Corrections Reception Center in Orient at 9:20 p.m. Tuesday evening. Castro was placed in protective custody in a single cell and was monitored every half hour, but not placed on suicide watch, which would have entailed round the clock monitoring by corrections officers.

"Make no mistake about it it is the duty of prisons officials to make sure that these types of things do not happen," said ACLU of Ohio's Gary Daniels.

Less than a month ago, death row inmate Billy Slagle was found hanged in his cell days before his scheduled execution. So far there have been a total of seven inmate suicides in Ohio this year.

"There needs to be some indication, certainly, that the department is taking this seriously in putting measures in place to minimize it and make it as rare as possible," said Daniels. "I don't know, given that this is the seventh suicide here in 2013 in Ohio prisons, that that's being done currently."

Ohio DRC Director Gary Morh says the special review team, chaired by Ed Banks, DRC’s Managing Director of Organizational Development, will include professionals from DRC’s legal, medical, mental health, security and operational divisions who are knowledgeable of DRC’s policies and procedures but who were not directly involved with the incident.

Mohr has requested that the review be completed by the end of the month.

DRC spokesperson JoEllen Smith says a similar review was done after Slagel's suicide. It has been completed, but hasn't been released yet.

The review into Castro's death is in addition to a separate, independent investigation being conducted by the Ohio State Highway Patrol.

The DRC is also reviewing Castro's medical and mental health care records. The review will determine whether applicable policies and procedures concerning the delivery of medical and mental health care were followed for Castro.