The teen accused of murdering his parents in California also allegedly had it out for his siblings and had long planned to kill them as well.

According to the New York Daily News, Orange County prosecutors said that Ashton Sachs, who shot and killed his mother and father as they slept in their multimillion-dollar mansion last month, also intended to kill every family member inside the house.

Authorities said that Sachs was attending college in Seattle and drove over 1,000 miles on Feb. 9 to his parent’s home and shot them, before opening fire on one of his sisters and his 8-year-old brother. A bullet missed the girl, but one hit the little boy, who is now paralyzed.

KTLA reported that prosecutor Ebrahim Baytieh said that part of the 19-year-old’s plan was to kill his siblings and that killing his family members was planned out over a “long period of time.”

“This was not something that happened at the spur of the moment or in the heat of passion,” said Baytieh. “This is a horrendous crime involving an adult man who decided to murder and kill the people who loved him the most, and the people who were supporting him.”