Of the 285,000 cold cases in the United States, just one in five will ever officially name a new suspect, and of those suspects, only one in 20 will be arrested. However, the latest breakthroughs in genetic identification allowed some cold cases to be solved in 2021.

For example, DNA evidence has finally confirmed that the 1971 death of 17-year-old Maureen Brubaker Farley in Iowa was caused by liquor store worker George Smith, something her parents had long suspected. In an older case, John Reigh Hoff was confirmed as the culprit behind the 1959 killing of 9-year-old Candice Rogers.

Although both Smith and Hoff died before they could face justice, other cold cases solved in 2021 have ended in arrests. For instance, Joseph Martinez, 49, was arrested for the 1999 murder of 13-year-old Minerliz Soriano after police possibly matched his DNA to semen found on Soriano's sweatshirt.