Update 7:15 p.m.
Samantha Herrera, 17, has been found, and Rodney Brown, 19, is in custody, the Colorado Bureau of Investigations tweeted.
It's unclear what charges Brown might face.
Authorities issued an AMBER alert for 17-year-old Samantha Herrera who is believed to be with a potentially violent man.
Herrera was last seen about 5 p.m. Tuesday in Sheridan. She is believed to be with Rodney Brown, a 19-year-old known to have guns, the AMBER alert said. Police said they are looking for either 2000 white Honda Accord with the Colorado plate OMB-236 or a dark blue Nissan Altima with Colorado plate UOF-493.
Herrera is 5 feet, 6 inches and weighs about 100 pounds. She has brown hair and brown eyes.
Brown is 5 feet, 10 inches and weighs about 150 pounds. He was brown hair and blue eyes.
Anyone with information on their whereabouts is asked to call the Sheridan Police Department at 303-795-4711.