Police in Eastpointe were trying to reach Johnathan Sails through his attorney to get him to surrender.
Sails was supposed to be monitoring a remedial swim class at East Detroit High School, just east of Detroit, on Nov. 8 when students told him KeAir Swift was having trouble in the water, according to Eric Smith, Macomb County's prosecutor.
Sails was sitting in the pool's bleacher area and initially told students Swift was fooling around, Smith said.
He then changed clothing in a locker room before jumping into the pool. A vice principal wearing a suit jumped in and pulled Swift out. The ninth-grader was resuscitated by an emergency crew but died after several days on life support.
Smith said a pool swimming monitor must be certified by the state as a lifeguard, in the immediate vicinity of the pool and have on clothing that allows easy access to the water.
"This was not the swimming team," Smith said. "This was a classroom of remedial swimmers. He was not in the immediate vicinity of them and he was not paying attention.
"Mr. Sails could have shown ordinary care and prevented this entire tragedy. Even someone that is not certified ... could have seen what was going on and stopped it before it got to the level that it did."
Sails was not certified to be a pool monitor, Smith added.
A message seeking comment was left for Sails. Involuntary manslaughter carries a maximum penalty of 15 years in prison.