The warden at Waupun Correctional Institution, a facility that is the subject of lawsuits and a federal investigation into a suspected smuggling conspiracy, has stepped down.

Randall Hepp announced his resignation in an email to prison staff Tuesday, the Wisconsin State Journal first reported. A spokesperson for the state Department of Corrections told the Associated Press that Hepp retired, rather than resigned.

In the email, Hepp said Brad Mlodzik, who previously worked as a deputy warden, will take over on June 30. Hepp praised employees for helping to improve safety and conditions in the prison.

Waupun has been the subject of a federal probe after a DOC sweep last summer uncovered banned items, including cell phones, drugs and other contraband. Five prison employees have resigned or been fired since the investigation began. The state placed 11 employees on administrative leave.

The smuggling allegations came at a time when the state’s correctional system was under fierce scrutiny from families of Waupun prisoners after a series of in-custody deaths and an extended locked-down period that lasted for nearly all of last year.

Dean Hoffmann, 60, died by suicide last June. His family has filed a lawsuit alleging prison staff were deliberately indifferent to Hoffmann’s serious mental health needs. The lawsuit says prison workers failed to give him his prescribed bipolar and antidepressant medications more than three-quarters of the time.

More: ‘I need answers’: Mother of Waupun prisoner who died of rare stroke files federal lawsuit

In October, 30-year-old Tyshun Lemons died of an accidental overdose of fentanyl. In March, Cameron Williams, 24, died of a rare stroke and fellow prisoners have accused prison workers of ignoring his pleas for help before his death.

The DOC is also facing a class action lawsuit, alleging “cruel and unusual” conditions at Waupun.

The department’s secretary, Kevin Carr, stepped down in March and was replaced late last month by the deputy secretary, Jared Hoy.

Vanessa Swales contributed to this report.

This article originally appeared on Milwaukee Journal Sentinel: Warden at Waupun prison, which is under federal probe, steps down