''The “blueprint” document was discovered after investigators mined more than 350 electronic devices seized from Heuermann’s home, according to Tierney.
“It had been erased and we used forensic tools to recover it,” the district attorney said.
The bail application said the Gilgo Homicide Task Force “believe that the totality of circumstances surrounding the … Planning Document, including Heuermann’s attempt to delete its existence, points to it as Heuermann’s self-education and ‘homework’ on the topic of carrying out serial, sexual murder.”
‘Thing to remember’ list of lessons learned
The “blueprint” document included a “pre-prep” section on steps to take before a killing, such as checking an area for surveillance cameras. A “prep” section appeared to outline what needed to be done closer to the time of the homicides, such as building a table with a “cross bar” underneath to support heavier objects, according to the bail application.''