DOUGLAS COUNTY, Colo. -- A hearing for a teenager accused in a deadly plot to attack Mountain Vista High School was delayed Friday.
Sienna Johnson is charged as an adult with conspiracy to commit first-degree murder and conspiracy to commit first-degree murder after deliberation.
Johnson's journal had the names of people she planned to target, prosecutors said during a motions hearing in January 2016.
Prosecutors said Johnson wrote that she and another person were going to be “unstoppable” and “prove what we are capable of.” Johnson also wrote they'd make the school "a living f***ing nightmare," according to the district attorney.
Prosecutors said Johnson bought a BB gun to practice her shooting skills and mapped out plans to attack Mountain Vista High School in Highlands Ranch.
Prosecutors said Johnson had a detailed map of where everyone in the school would be and knew the school resource officer schedule.
Johnson's alleged co-conspirator pleaded guilty last month to conspiracy to commit first-degree murder.
Brooke Higgins will likely serve two years in a youth correctional facility and another four years under intensive probation after she completes her facility sentence. Her sentence will be finalized at a hearing Feb. 8.