Seventeen-year-old Diana Nielsen was last seen in Longmont, Colorado, on September 17, 2024. She is described as White/Caucasian, 5 feet 5 inches tall, about 130 pounds, with brown hair and brown eyes. Her case is registered with the National Center for Missing & Exploited Children and is being investigated by the Longmont Police Department.

Authorities have not released details about her last known movements, what she was wearing, or her state of mind, which has complicated the search. Family, friends and the community remain involved while investigators urge anyone with information to come forward.

Did anyone in Longmont or the surrounding area see Diana around mid-September 2024 or have information that could help locate her?