DOUGLAS COUNTY, Colo. (CBS4)– The second of two teens accused in a murder plot at their high school pleaded guilty to several charges on Wednesday. Sienna Johnson was charged with making threats against Mountain Vista High School.
Johnson, who is now 17 and was 16 at the time of her arrest, appeared in court on Wednesday. She pleaded guilty to felony menacing, conspiracy to commit murder and being an aggravated juvenile offender.
Johnson will be sentenced to five years in the Department of Youth Corrections followed by four years probation. Formal sentencing is scheduled for Aug. 11. Once she turns 21, the Department of Youth Corrections loses jurisdiction and the judge can re-evaluate her sentence at that time.
According to the arrest affidavit, Johnson and Brooke Higgins were planning a shooting at their high school on Dec. 17, 2015 with Johnson planning to kill her mother and sister prior to the shooting at the school.
The girls were then planning to commit suicide after the shooting at the high school.
Brooke Higgins pleaded guilty earlier this year to her role in the plot, including charges of conspiracy to commit murder and solicitation to commit murder, both felonies. She has been in custody since her arrest.
In the plea agreement, Higgins, now 17, was sentenced to three years in the juvenile detention system followed by four years of supervision. She received credit for the time she has served so far.