Illinois health officials have issued a warning to parents of children treated by a Chicago-area pediatrician that he hinted in a suicide note at defying parents’ wishes and not vaccinating some patients. According to news station WGN-TV, Dr. Van Koinis took his life in September at the age of 58. He wrote in his suicide note that he may not have given children vaccinations despite the requests of some parents, and said he felt guilt over the way he handled some vaccinations over the past 10 years. Cook County investigators say it is not clear which children were properly vaccinated and which ones were not due to record-keeping issues—but some records indicate that some children were not given their vaccines.

“We have no real ability at this point to be able to narrow the scope,” Cook County Sheriff Tom Dart said. “All we can say is that a person that was very well-respected, well-liked doctor for many, many years committed suicide and left a note that was very clear that he had horrible regrets for how he acted, specifically during a 10 year time frame leading up to now. And specifically as it applied to vaccinations and the records that are kept in regards to that.” Officials also urged the parents of Koinis' former patients to contact their new doctors. OSF HealthCare, a network affiliated with Koinis’ practice, said he ran a “private practice” as an “independent physician” but that they would cooperate if contacted by law enforcement.