PAW PAW, Mich. (WOOD) — “Tried using electrical tape to make a longer fuse,” then 15-year-old Aidan Ingalls wrote back in 2018 as he made plans to bomb and shoot up Paw Paw High School.

“Shrapnel is the 2nd part of a bomb that’ll be sure to kill/injure many people,” he wrote.

Screws, he added, make for good shrapnel: “More painful.”

Van Buren County investigators on Wednesday released 250 pages of documents outlining the evidence from three years ago that they say should have kept Ingalls off the streets. They had gathered the evidence after Ingalls had threatened to terrorize his own school.

It was evidence they hoped would have convinced a judge to treat Ingalls as an adult in 2018, in which case he would have been still be locked up.

If that had happened, they said, Ingalls would not have shot Charles Skuza, 73, and his wife Barb, 71, on the south pier at South Haven. Charles Skuza died. His wife was hospitalized in critical condition. Ingalls shot himself to death.

“The reality is this is one of those cases that could have been preventable, and it wasn’t,” Paw Paw Police Chief Eric Marshall said at a press conference earlier this week. “Judge Dufon made the wrong decision in this case.”

It was Ingalls’ mom who confronted him on March 18, 2018, then walked him to the Van Buren County Sheriff’s Office. He admitted that he had planned to detonate Molotov cocktails at Paw Paw High School that day, then shoot up students and staff. He had already created a 27-name hit list, had experimented with explosives, and had cut down two shotguns stolen from his grandfather.

“Aidan said he would save the last bullet for himself,” police wrote in a report.

The evidence also included his internet research of the Ku Klux Klan and Nazis, his drawing of a hooded Ku Klux Klansman and of a gunman wearing a hat with an anarchy symbol.

After a hearing in 2018, Judge Jeffrey Dufon sentenced Ingalls as a juvenile to inpatient treatment.

Just last month, the judge discharged Ingalls from all supervision.

Then, last Friday, the 19-year-old randomly shot the Skuzas at point-blank range on the South Haven south pier before killing himself.

News 8 hasn’t been able to reach the judge for comment, but the chief judge in a written response said the prosecutor at the time agreed with the ruling to treat Ingalls as a juvenile and did not appeal it.