Gov. Tim Walz’s Human Services commissioner has resigned just six months after being appointed.

The governor’s office announced Tony Lourey’s resignation on Monday without explanation. He leaves just days after two deputy commissioners announced their departures — also without explanation.

Lourey was a Democratic state senator when Walz named him in January to head up one of the state’s biggest agencies. But Human Services has been under fire for its handling of alleged fraud, data breaches and other administrative problems.

Walz said in a statement that Pam Wheelock would take over as acting commissioner. Wheelock was commissioner of finance under Gov. Jesse Ventura.