'Dangerous' teen faces adult charges in Mountain Vista High School murder plot; Bond set at $1M

Psychiatric evaluation ordered for 2nd teen girl

HIGHLANDS RANCH, Colo. - One of two teens accused of planning a deadly attack at Mountain Vista High School in Highlands Ranch faces adult charges, the District Attorney announced Tuesday.

Denver7 has confirmed her name is Sienna Johnson, 16, and is identifying the teen because of the adult charges. 

A judge announced the elevated charges in court on Tuesday afternoon. Johnson was formally accused of conspiracy to commit murder and conspiracy to commit murder after deliberations. Her bond was set at $1 million. Denver7 reporter Jennifer Kovaleski was in court for the hearing. Kovaleski said Johnson showed little emotion but she cracked a few smiles at her lawyers. 

Johnson had been on a psychiatric hold since her arrest. 

Someone notified Mountain Vista High School about the threat over the Text-A-Tip line on Saturday, Dec. 12. The specific nature of the threats hasn't been released. Many details of the case have not been made public, because court documents are sealed.
However, Denver7 learned many new details in court Tuesday afternoon once the decision to charge Johnson as an adult was announced. Prosecutors said Johnson had a detailed map of where everyone in the school would be and knew the school resource officer schedule. They added that Johnson already bought a BB gun to use for target practice. The prosecution called her extremely violent and said she harmed pets in the past.
Prosecutors alleged Johnson wrote about "NBK" in her journal, which stands for natural born killers and was an obsession of the Columbine shooters, and drew "disturbing" images there. They said Johnson hasn't shown any remorse, and she told detectives that if she was free, she'd attempt to execute the plot again.

The second girl will be identified as well if she's charged as an adult. A psychiatric evaluation was ordered for the second 16-year-old female suspect, who appeared in court on Tuesday morning. Her lawyers claim that investigators have centered their case around her therapy journal and her cell phone, which they say were seized without proper consent.

Denver7 spoke by phone with a family member after the teens were taken into custody in mid-December. She was upset and began to cry on the phone.

"We're exhausted," the Jennifer Johnson said. Asked how the family was holding up, she said, "Not well," and added that she couldn't comment on the case or how Sienna was doing.

The decision to announce whether the second girl will be charged as an adult has been delayed until next Thursday, after the psychiatric evaluation is complete. Both girls had been held on investigation of conspiracy to commit first-degree murder.

Attorneys for the girl who appeared in court Tuesday morning said the prosecution's case is not strong, and they are fighting a news media request to unseal court documents.

"There is no direct evidence in this case of Defendant’s possession of any weapons, bombs, or incendiary devices," attorneys stated. "Instead, the prosecution’s theory hinges upon entries written in Defendant’s personal journal, which was seized by law enforcement without a warrant and without consent of either Defendant or her parents."

The personal journal was written at the urging of the girl's professional counselor as part of ongoing therapy, attorneys said.

"Additional evidence which forms the basis of these charges derives from the unconstitutional seizure of Defendant’s cell phone during a meeting with law enforcement officers," attorneys stated. "It is highly likely that some or all of the evidence upon which these charges are based may be suppressed because of significant Fourth Amendment violations by law enforcement."

In the hearing, they discussed getting a search warrant to go through the girl's cell phones.

Investigators determined the threat was credible and said the tipster - believed to be a student - saved lives.

"I think the text message and the information we obtained through our investigation saved lives for sure given the severity of the situation," Douglas County Sheriff Tony Spurlock said.

Another hearing is scheduled for Jan. 13 to discuss unsealing documents in this case.

MORE | 2 students arrested after threat to Mountain Vista High School in Highlands Ranch


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