The remains of an Illinois woman who vanished in Chicago more than five years ago have been found, her family says.

Cheyann Klus, of Downers Grove, was 22 in December 2017 when she was "reported missing by her father after she had not returned home after a few days," according to the Cook County Sheriff's Office. 

Police say prior to the discovery of her remains, her last known contact was with a friend in Chicago that year.

"We have been looking for Cheyann, and information related to her disappearance, since she went missing over 5 years ago. While it was not the news we were hoping for, we have received confirmation from law enforcement that Cheyann’s remains were found," her sister, Mariah Klus, wrote on Facebook.

"As her immediate family [father, sisters, brothers, nephews] in mourning, we ask for privacy as we grieve the unbearable loss of a daughter, sister, aunt, and a human being," Mariah Klus added. "We plan to hold a private memorial service for Cheyann amongst us, but we hope that everyone can find solace in knowing that she has been found and respectfully laid to rest."

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Cheyann Klus remains found

Police say Cheyann Klus, 22, last was verified to have contact with a friend in the Hermosa neighborhood of Chicago on Dec. 1, 2017. (DuPage County Sheriff’s Office)

The circumstances surrounding Klus' death were not immediately clear.

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Cook County Sheriff's Office police car

The Cook County Sheriff's Office says it is working with Chicago Police to investigate Klus' death. (Cook County Sheriff's Office)

Two police searches of the Mallard Lake Forest Preserve in Hanover Park during the time of her disappearance, involving more than 100 personnel and five dogs, came up empty, Fox32 Chicago reports.

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"The Sheriff’s Office worked closely with the DuPage County Sheriff’s Office and the FBI to successfully identify the remains of Cheyann Klus through dental records last week," the Cook County Sheriff's Office told Fox News Digital in a statement Tuesday.

"The Sheriff’s Office will continue to work with Chicago Police to investigate the circumstances of her death, but we are grateful to help bring some measure of closure to Klus’ family," it added.