On the board of "children across the country," the name Rolly Deschain appears, a reference to Roland Deschain from King's Dark Tower series.
On the wall of the interrogation room is the hashtag "#escapetohaven". This is a reference to the web series released between the 2nd and 3rd seasons.
Dr. Lucassi says the lungs were "diseased, sclerotic." While sclerotic refers to thickened and stiff tissue, a lung with stiffened, thick tissue is generally called fibrotic.
Nathan an the other detective search for the suspect on Currey st. Tim Currey played Pennywise in the "It" miniseries based on the Stephen King book of the same name.