Lisa Swarn wrote in the guest book accompanying Koinis' online obituary that he was still her doctor, even though she was nearly 30.
"Dr. Van Koinis was more than just your ordinary doctor," Swarn wrote. "I am lost with words over the fact that he is no longer here with us. I will NEVER find another doctor like him and it fills me with sadness."
Cook County Sheriff Tom Dart said a suicide note left behind by the pediatrician contained some alarming statements.
"The note was very short," Dart told CBS Chicago. "It was a note where he expressed a lot of regret, and the note was solely driven at the fact that he did things he regretted as far as the vaccinations.
“He was incredibly regretful for what he did, and it was the only thing he mentioned in the suicide note. It was this and only this.”
The note turned the investigation of the doctor’s death upside down.
"It started off as a straightforward investigation of a missing person that led to a case of suicide, and then from there, we came across a suicide note," Dart told the Tribune. "In the note, it referenced concerning things in regards to the doctor's practice and his possible motivation as to why he killed himself."
Pictured in a November 2018 Street View image is the Evergreen Park, Ill., office building where Dr. Van Koinis practiced. Koinis, 58, was found dead of a self-inflicted gunshot wound Sept. 10, 2019, in a forest preserve in Palos Township. The pediatrician is suspected of forging vaccination records of his patients over a 10-year span before his death. (Google)
Dart told the Tribune and the Chicago Sun-Times that Koinis wrote of becoming "averse" to immunizations in the final decade of his practice, which he conducted in an office on West 95th Street in Evergreen Park, a village about 15 miles south of Chicago.
Koinis was known for his use of homeopathic remedies, which officials fear may have drawn parents seeking fraudulent proof that their children had received the immunizations required to attend school, the Tribune reported.
"He was well known for being someone who was into homeopathic medicine, and from what we have determined, it was well known that people opposed to vaccination could go to him," Dart told the Tribune.
Illinois state law requires parents to show proof of vaccinations when enrolling their children in school.
Koinis referenced his immunization record-keeping in the note, the sheriff said.
"It came off to us that he meant immunization records were fraudulently filled out," Dart told the Sun-Times. "There are concerns which immunizations were given or not given."
“We took (the note) very seriously and tried to find the scope of it, but we couldn’t,” Dart said.
Authorities are now trying to reach parents whose children were patients at Koinis’ practice so they can ensure their children were inoculated as needed.
The biggest concern, Dart said, is whether Koinis failed to vaccinate children whose parents went to him seeking the inoculations. The newspaper reported that no evidence has been found to confirm Koinis was failing to vaccinate those children.
Multiple parents came to Koinis’ defense, saying they personally witnessed either the doctor or his nurse administering vaccines to their children.
"I'm the mother," one parent, Beata Przeradzki, told the Tribune. "I was there. I saw it."
Another mother, Mary Mullaney, told CBS Chicago, however, that something seemed amiss when she took her now-13-year-old son to Koinis for his 12-year vaccinations.
"He was just very different. He wasn't the same doctor that I had been taking my kids to," Mullaney told the news station. "He had always been stuck on, like, the technology aspect, of technology ruining children's brains, but this visit, I mean, I sat there for about 45 minutes, and he kept going on and on and on. I was just there for the checkup, and he actually ended up telling me that my son didn't need the vaccines that the school had said."
Mullaney said she believed Koinis until her son’s school contacted her and said he required the vaccines before he could return to class.
"So when I went back to Dr. Koinis, he was kind of surprised. We got the shots. He gave it to him. I hope that's what he gave him," Mullaney told the CBS affiliate.
At least one woman on the West Elsdon Facebook community page alleged Koinis' death was not suicide but murder.
"This poor man was killed. It's a murder-suicide (because) he didn't promote vaccines, which do cause autism," Rebecca Hernandez wrote. "Look up 'holistic doctors murdered.' The numbers are alarming and tells you they ARE being killed by big pharma or the feds."
Despite widespread belief among vaccine opponents that childhood inoculations cause autism, reputable studies have shown that isn't the case. According to the Centers for Disease Control and Prevention, no link has ever been found between autism and the ingredients in vaccines.
Dart and other officials are asking parents whose children were seen by Koinis to have their new pediatricians confirm, where possible, that the children have been vaccinated. Dr. Tina Tan, a pediatrician at Lurie Children's Hospital, told the Tribune blood tests can confirm some of the typical vaccines given to children.
"When anybody gets a vaccine, you should develop antibodies to that vaccine," Tan said.
While the antibodies would show up in the blood, it is unclear for some vaccines, like the pertussis vaccine, what level of antibodies are considered protective, Tan told the newspaper. She said it would take multiple tests to determine but that enough blood for the tests could be taken in a single draw.
"They're going to have to draw blood on these children. That's not the easiest thing," Tan said.