Waseca County prosecutors cast a wider net Friday, charging an adult and two teens in connection with the high-profile case against a local student accused of planning to kill his family and set off bombs at his school.

A Waseca man was charged with one count of selling a pistol to a person younger than 18 without notifying authorities. The boy who bought the gun, 17-year-old John LaDue, was arrested in late April after police learned of his plans for a Columbine-style massacre.

Two juveniles, both 17, were each charged with possessing and making explosive devices with LaDue. Some of the explosives were set off at a park and school ball fields, although charging documents say the accused teens did not know of LaDue’s plan to use explosives to kill students.

Prosecutors allege that LaDue was close to carrying out a plan, detailed in a 180-page notebook, to kill his mother, father and sister, then create a diversion for first responders so he could go to Waseca Junior/Senior High School to carry out a massacre.

LaDue has been charged in Waseca County District Court as a juvenile with four counts of attempted murder, two counts of first-degree damage to property and six counts of possession of a bomb by someone under 18. Prosecutors are trying to certify him as an adult.

According to charging documents, Michael S. Jacobs, 40, admitted to selling a .45 caliber Llama handgun to LaDue in summer or early fall of 2013.

The documents say Jacobs said he needed money and asked his son, a friend of LaDue’s, to put out “feelers” to see if anyone wanted to buy the pistol. The son said Jacobs required a note from LaDue’s father saying it was OK. LaDue’s father told police he didn’t know his son was buying the pistol until he came home with it, however. Jacobs sold the gun and one magazine to LaDue for $350 and failed to report the sale to local police, the charges say.

Reached at his Waseca residence, Jacobs’ wife, Dawn Jacobs, said that she didn’t know details but that her husband thought that he was selling the gun to LaDue’s dad, not LaDue.

“If he would have known, he would have never sold it,” she said.

Other charging documents allege that one of the teens charged Friday morning used his debit card to buy 15 pounds of potassium perchlorate from a website and had it shipped to LaDue’s house, with LaDue paying him back for the powder. The boy admitted helping make “crickets” by putting black powder into an empty CO2 cartridge and then exploding some of the devices on a slide in a Waseca park. The boy also admitted that he and LaDue made another explosive out of thermite and detonated it on an aluminum bench near school ball fields.

The second juvenile also admitted helping to make two crickets in the upstairs of a home, then trying and failing to set them off in soccer fields at the school with LaDue.

Authorities said they found LaDue with bomb-making materials in a storage locker in late April, after a 911 caller grew suspicious when she saw the teen go inside and close the door.

LaDue soon told authorities that he had intended to kill “as many students as he could,” according to the charges, by setting off pressure cooker bombs and gunning down students in the halls.

Jacobs is expected to appear in court on the felony charge on July 8.