IONIA, Mich. (WOOD) — An Ionia therapist accused of the sexual abuse of a patient was formally charged Thursday with nine criminal counts.

Derek Robertson, 50, of Lowell, was arraigned on three counts of fourth-degree criminal sexual conduct, a high-court misdemeanor; three felony counts of health care fraud and three felony counts of delivery or manufacture of a controlled substance. A not guilty plea was entered, which is standard at arraignment.

Robertson said little, only acknowledging he understood the charges against him and answering questions briefly.

The CSC charge stems from the alleged sexual relationship between Robertson and his patient that state investigators said lasted for nearly a year and a half. Investigators said Robertson admitted to having sex with his patient in his office and at his home. In Michigan, it’s illegal for mental health professionals to have sex with clients, regardless of consent.

“It really cannot be understated how manipulative the defendant was with his patient,” Ionia County Prosecutor Kyle Butler said in court. “The abuse of the mental health professional and patient relationship is frankly staggering when you think about the whole reason why she was going in the first place, and a lot of it had to do with a prior history of traumatic experiences that she had experienced in her life.”

The state also says Robertson admitted that he continued to bill the woman even when they only had sex during appointments.

In late March, Viewpointe Counseling in Ionia posted on Facebook confirming Robertson was no longer working there. His license was suspended April 10, which means he can’t currently practice. In court, he said he was unemployed.

Butler said Robertson turned himself in to the jail Thursday morning. His bond was set at $15,000 cash or surety. He was ordered not to have any contact with the victim in the case and to undergo regular alcohol and drug testing.

His next hearings are scheduled for May 31 and June 7.