Kenia Monge mysteriously disappeared from a downtown Denver nightclub on April 1.
Sometime after midnight, Monge's friends said they saw her with a man they did not know.
"I called her phone the first time, then the second time and then some girl picked up," Laith Essmail, Monge's boyfriend, said. "I was like 'Hello, hello?' and she was like, 'Hey, this is Kenia's friend. We lost her at the club. Do you know how to get in contact with her?'"
Essmail says Monge's cell phone was the only way to get in contact with her. She left her phone and purse behind at the 24K nightclub.
Essmail and Monge started dating over the summer. Monge moved in with him a couple months ago.
"It's the craziest thing I've ever gone through in my entire life," Essmail said, referring to Monge's disappearance.
Denver Police wouldn't elaborate too much on the case. They only said they're upping their investigation.
"We've been searching everywhere where we are given information. We've been in and out of Denver already and looking in numerous locations," Lt. Matt Murray with the Denver Police Department said.
A witness told police he spotted Monge at the Conoco gas station off of Speer Boulevard and Pennsylvania Avenue a few hours after Monge left the nightclub.
Monge is 4 feet 11 inches tall and 115 pounds. Police say she was last seen wearing a black skirt, black jacket and red high-heeled shoes.
(KUSA-TV © 2011 Multimedia Holdings Corporation)