HUDSONVILLE, Mich. (WOOD) — Court records show a 16-year-old boy with severe autism was living in a “deplorable” bedroom before he was found face-down and not breathing in the family’s backyard swimming pool in March.

His father Timothy Koets, 50, was arraigned Friday morning on charges of involuntary manslaughter, second-degree child abuse, second-degree child abuse committed in the presence of another child and fourth-degree child abuse.

Koets, a Grand Rapids Community College professor, was arrested Thursday. If convicted of manslaughter, he could spend 15 years in prison.

The second-degree child abuse charge is for leaving the child unattended in the backyard and the fourth-degree charge for having an unsafe bedroom, improperly binding a child’s hands and leaving a child unattended.

Sam Koets was 16, but his mental development was stalled at about the level of an 18-month-old, according to behaviorists.

Sam was at his home near Hudsonville with his father on March 28. His mother was asleep and his older sisters were not home, according to a probable cause affidavit News 8 received Friday.

The father allegedly told police that Sam liked to turn in circles for hours and that because if his severe cognitive limitations, his arms were restrained to keep him from injuring himself.

Timothy Koets said he put the boy on the porch outside, a few yards away from a tarp-covered , easily accessible above-ground pool.

The father said he had to leave the house and woke up his wife to tell her Sam was outside.

According to investigators, Koets “acknowledged that he probably should have waited to make sure that she was more woken up.”

Sam’s 18-year-old sister arrived home to find Sam standing up in the water. However, she thought nothing of it because she often saw him unattended outside.

Later, his 14-year-old sister texted their father a picture showing Sam standing chest-deep in the middle of the pool, which had ice floating in it.

Police say the father texted the 14-year-old girl asking, “would you make sure the freak is okay?”

Authorities were not called until more than an hour after Sam was first observed in the pool.

He was declared dead at the scene from drowning.

Investigators found that Sam’s basement bedroom was “deplorable,” with fecal matter and dirty diapers found throughout the room.

Children’s Protective Services had visited the Koets’ home multiple times. In October of 2014, Koets and his wife has substantiated charges of “improper supervision and threatened harm” with regards to Sam and his younger sister.

Multiple times throughout 2015 and 2017, CPS developed safety plans for the Koets, specifically regarding Sam being around water. CPS also gave them door alarms, which were allegedly never used.

CPS also alleges that the parents had “a history of illegal substance abuse.”

This all flies in the face of the professional image of Koets, a respected 23-year veteran of Grand Rapids Community College as a professor of computer sciences.

“He was a very good professor, definitely the best online professor I’ve had and he was always very helpful in person as well,” GRCC student Chris Talbot said.

Koets was often sought out as an expert in computer technology.

“He was definitely respected in his field. He was one of the more popular professors for computer science stuff, all the computer science students know him,” Talbot said.

Talbot set up a GoFundMe account for the professor after learning of his son’s death.

“I wanted to help him when his son died in that accident, so I set up that GoFundMe and through that I developed more of a connection with him and we talked a little bit about his family,” Talbot said.

Koets asked him to make changes in the wording of the GoFundMe.

“He said the media was trying to portray it as a sort of negligence and he said he want to make sure it was very clear that it was not. He was very adamant about that,” Talbot said.

The student had no reason to doubt his respected mentor.

“I trusted him when he said that it was just a tragic accident. His story had a few things that I was like, ‘That doesn’t make sense to me but I’m not going to probe because his son died,’” said Talbot, adding that the charges have been shocking. “It was a drive home from work, I was shaking, I cried a little. It’s been tough.”