A teenager in Wisconsin confessed to killing two of his grandparents and even typed up a plan for the attack, the AP reports.

Alexander Kraus was charged on Sunday in Appleton, Wisconsin with two counts of first-degree intentional homicide in the deaths of Dennis Kraus and Letha Kraus, aged 74 and 73 respectively.

Alexander Kraus, 17, reportedly typed out “several pages” outlining his plan to shoot and kill the couple.

According to a criminal complaint released Tuesday, the pages were found in a red folder and do not include a motive for killing Kraus’s grandparents.

The AP notes that the complaint also “mentioned a book found in Kraus’s camouflage backpack about an executioner.”

Kraus, who is a junior at Neenah High School in Wisconsin, reportedly told investigators that he was planning to “cause harm” to his high school, but details of his plans have not been revealed.

Police determined that the students and teachers were in no immediate danger, and school proceeded as usual on Monday.

Alexander Kraus reportedly spent the night at his grandparents’ home before killing them.

Police found a shotgun with a knife taped to the end of barrel on a bed in the home of the Kraus grandparents, whose bodies were found in their kitchen.

A search through the house also revealed a second shotgun, two gun cases, a “large amount of various ammunition,” and an undisclosed number of other guns in a gun cabinet.

Police say Dennis Kraus was shot once in the head, while Letha Kraus was shot once in the arm and once in the head.