cold case

American  

[kohld keys] / ˈkoʊld ˈkeɪs /

noun

1. a criminal investigation that has remained unsolved for an extended period of time.

   This year's award recipient is a state trooper whose work helped close a cold case from 1983.

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Etymology

Origin of cold case

First recorded in 1970–75

Example Sentences

However, the investigation was reopened as part of a cold case review in 2023 and Sharp's DNA was found to match a profile of the attacker.

From BBC

A month, from an investigative standpoint, is not a long time, Morgan added, noting that he doesn't think "this is anywhere close to a cold case".

From BBC

Four moms teamed up during the pandemic to solve a cold case murder, becoming close friends.

From Los Angeles Times

Welsh actress Eve Myles is set to star in a crime drama inspired by the true story of a detective who solved the cold case murder of a 17-year-old girl in the 1980s.

From BBC

Still, experts say it’s far too early to call this a “cold case” and noted a break could come at any moment.

From Los Angeles Times