CASTLE ROCK, Colo. -- One of the two 16-year-old girls accused of a plot to attack Mountain Vista High School pleaded guilty Tuesday.
Brooke Higgins pleaded guilty to conspiracy to commit murder and solicitation to commit murder at the Highlands Ranch School. She was accused of plotting a Columbine-inspired attack last year.
She is expected to be sentenced to three years in a juvenile facility and then four years supervised probation.
Higgins and alleged co-conspirator Sienna Johnson were charged as adults on two felony counts of conspiracy to commit first-degree murder.
Prosecutors have previously said Higgins searched online to see if underage children could buy guns and if they could purchase firearms at a gun show.
Higgins also wrote in her journal that she wished she could have done the Columbine attack and that she searched about previous female gunmen, prosecutors said.
They also said Johnson made detailed maps of Mountain Vista High School, including specific locations of deputies who were assigned to protect the campus. Her next court appearance is in January.
The plan was foiled in December 2015 after the Douglas County Sheriff's Office was tipped off to the threat that led to the arrests.