Melissa Whitsitt and Svetlana Ustimenko go missing within days of each other in Winter Park, Colorado, as mystery grows over their disappearance

Mystery surrounds the disappearance of two women who went missing within days of each other from a small vacation town in Colorado.

Melissa Whitsitt, 34, was last seen on August 13 at the 100 block of Woodspur Lane in Winter Park and did not show up for work that day.

Her phone was used to make several phone calls the same day from an unknown man in the Denver area, but has since been turned off.

Days earlier, on Aug. 11, a short drive away in the Deadhorse Trailhead area off Grand County Road 73 in the Arapaho National Forest, a search began for 55-year-old Svetlana Ustimenko.

Authorities have reassured local residents by saying the two cases are unrelated and do not pose a threat to the community.

Mystery surrounds the disappearance of two women who went missing earlier this month from a small vacation town in Colorado. Melissa Whitsitt (left), 34, went missing on Aug. 13, while the search for Svetlana Ustimenko (right), 55, began Aug. 11.

Authorities have reassured local residents by saying the two cases are unrelated and do not pose a threat to the community.

Whitsitt had moved to Colorado in May to work at the Winter Park Resort, but was reported missing on August 13 when she failed to show up for work, the Grand County Sheriff’s Office said.

Investigators investigating her disappearance found that an unknown man had been using her phone to talk to people in Denver the day she disappeared.

Her parents, Cindy and Jerry Whitsitt, drove to Winter Park from western Tennessee to look for their daughter within five miles of Union Station.

They handed out flyers and asked if anyone had seen her.

“Like a needle in a haystack,” Cindy said CBS news. “Some law enforcement officers were very eager to help us, but they are understandably outnumbered. There are literally two detectives on the department here in Denver and we found that unacceptable.”

Whitsitt, 34, was last seen on August 13 at the 100 block of Woodspur Lane in Winter Park and did not show up for work that day

Her mom Cindy Whitsitt shared two photos of what she looked like before, hoping someone will recognize her

The family grew up in Tennessee and said Whitsitt was extremely excited to start her new life in Winter Park.

Her mom Cindy said, “She’s a livewire. It always has been, she is very loud; you’d see or hear her if she’s out there somewhere.”

Whitsitt hasn’t used her debit card lately and hasn’t contacted her friends or family.

Cindy shared two old photos of Whitsitt with blonde hair on Facebook, saying “there are reasons for the three different photos.”

In a separate case, Ustimenko’s rental car was found parked in the Deadhorse Trailhead area in late July.

The vehicle was due to be returned on Aug. 10, but it sat “for an extended period” with no sign of her, authorities said.

Ustimenko’s car was seen parked on a trail in July, but a search for her did not begin until August 11

The investigation revealed that Ustimenko, who is from Florida, was recently diagnosed with a terminal illness and that she “had a hard time trying to cope and was drawn to the mountains of Colorado.”

A team of local authorities, combined with search and rescue teams and cadaver dogs, has been searching the area since August 11.

Officials were unable to locate Ustimenko, despite the help of off-route ground rescuers, drones, horses and 750 volunteer hours.

The sheriff’s office concluded she was not in the primary area and the search was suspended Tuesday pending new information.