A nurse at Minnesota’s Veterans Affairs Medical Center has been charged with regularly stealing pain medications over a six-month period from the hospital last year.

Matthew Leininger, 42, who was fired from the hospital in March, stole drugs such as fentanyl, morphine and oxycodone on more than 70 occasions, according to a criminal complaint filed this week. He told investigators he needed the drugs to cope with mental health issues, according to prosecutors. He faces five counts of felony theft by swindle.

According to a criminal complaint, the medical center uses a machine called Pyxis to dispense drugs to doctors and nurses. Leininger was required to log in with his user identification and provide his fingerprint to obtain the drugs, then enter into a machine which patient will receive the drug and record the dose to be administered. Then the nurse is expected to log in how much was given to the patient or the amount that was wasted.

By reviewing the records, investigators determined that Leininger followed the procedures for obtaining the drugs, but did not record that the drugs were administered to the patient he had designated or wasted, according to the complaint.

In addition to those 34 days, in another 31 cases, Leininger did record a partial administration of the drug, but did not record the resulting waste or recorded a partial waste of the drug but not of the administration of the rest of it to a patient. With multiple thefts on some of those 34 days, Leininger is suspected of stealing drugs more than 70 times.

Investigators spoke to Leininger on Dec. 28 and his ability to access the drugs was ended and he was fired in March.