WHEATON, Ill. (CBS) — A 19-year-old former student at Glenbard East High School in Lombard was in custody on Wednesday, accused of planning a “Columbine-style” attack on the school, with a list of people he wanted to target.

The details of the planned attack on Glenbard East were found in a journal that 19-year-old Michael Santoro had been keeping, according to DuPage County State’s Attorney Robert Berlin.

“Including mentioning a Columbine-type shooting at Glenbard, and also mentioning that this would be one of the saddest days in Lombard, and would be remembered forever,” Berlin said.

Berlin said, in February, Santoro told an acquaintance about the plan. Two weeks ago, the acquaintance told authorities.

A tactical vest was found in Santoro’s Lombard home, along with some ammunition, according to Berlin.

Santoro’s journal included a list of apparent targets, and the deans at Glenbard East were at the top of the list, Berlin said. It also mentioned the high school graduation on May 31, but it’s unclear if that’s when he allegedly planned an attack.

Santoro has been charged with felony disorderly conduct, and misdemeanor possession of drug paraphernalia and possession of ammunition without a Firearm Owner’s Identification card. A judge has set his bond at $500,000. If he posts bond, he would be placed on home confinement and electronic monitoring.