SALEM — A doctor at the Oregon State Hospital claims he was forced to resign after an investigation into a patient death.

Dr. Michael Robinson was under internal investigation for his treatment of a patient who died last year at the psychiatric hospital. A spokeswoman for the Oregon Department of Human Services said Tuesday the investigation had been completed.

The Statesman Journal reported that Robinson attempted to withdraw his resignation offer but it was rejected by hospital officials, who ordered him to turn in his identification and pick up his final paycheck at the end of July.

In a July 9 letter to the hospital’s chief medical officer, Robinson asserted that his “resignation offer was made while I was under great duress from threats of adverse employment actions.”

The letter also said that it was Robinson’s understanding “that if I resigned, the hospital would cease their baseless and misguided efforts to damage my reputation as a medical professional.”

Robinson has denied allegations he failed to provide Moises Perez, 42, with adequate medical care before Perez died last October. An autopsy showed Perez died of heart disease.

Robinson had been relieved of direct patient care in April pending results of an investigation into the treatment of Perez.

The hospital’s chief medical officer, Mark Diamond, stated in a July 14 letter to Robinson that July 31 would be his last day of employment.

In his letter, Diamond defended the hospital’s actions in dealing with Robinson.

Hospital officials “have not set out to damage your reputation, and the actions undertaken to date have not resulted in so-called stigmatizing circumstances,” Diamond wrote.

The Statesman Journal obtained the correspondence between Robinson and the hospital on Monday through a public records request.

In June, five veteran employees received letters of reprimand for their shortcomings involving Perez. At the time, officials said that a separate review was continuing to look into the medical care of Perez.

Investigators reported that Perez’s caregivers on Ward 50F failed to properly treat his chronic medical conditions, failed to develop a proper treatment plan for him, failed to update his medical chart and failed to return calls from his family in the last weeks of his life.

Robinson had gained some support from Oregon AFSCME, the union representing some hospital employees, over his attempt to withdraw his resignation.

“Any discontinuation of Dr. Robinson’s employment will be treated as a disciplinary discharge and subject to the grievance and arbitration procedures of the contract,” Jason Weyand, the union’s legal counsel, wrote to Diamond on July 16. But the hospital rejected the union’s request for fast-track arbitration of the dispute.

Cheryl Miller, senior human resources manager, said in a July 26 letter to Weyand that Robinson voluntarily resigned from OSH.

“Here, OSH accepted Dr. Robinson’s resignation, which was initiated by him, legitimately tendered, and reflected a voluntary decision to end his employment,” Miller wrote.