Over the past 20 years, dozens of homicides have gone unsolved in Orange, Ulster and Sullivan counties. There are other, older unsolved cases, too, and cases in which no one knows the victim’s name.

Each case has its own unique challenges, and each case carries its own arc of frustration, grief and tragedy.

Since 1988, there have been roughly 421 slayings in Orange, Ulster and Sullivan counties that were charged or classified by police as murders. Of those, 59 are unsolved.

These cases run the gamut of circumstance. There are public killings such as the Jan. 1, 2016, slaying of Justin Speights at a crowded party in the Town of Crawford. There are locked-door whodunits like the 1999 stabbing death of Martha Green in the City of Newburgh. There are cases where fire was used as a weapon and a tool of concealment, such as the 2001 killing of Karen Gruber in the City of Newburgh and the 2008 killing of Michael Kleiman in the Town of Ulster.

There are cases where all police have is a skeleton or a partially decomposed body. There are mysteries like the slayings of Larry Atkins and Robert Gordon in 1992 and 1996, separated by two miles and four years, but connected by strong similarities between the victims and how they were killed.

In most cases, there are family and friends plagued with unanswered questions about how or why their loved one died. They don’t know who committed the murder. Could it be a neighbor? A friend? Someone they trust?

In some cases, there is no one left to mourn the victim, just police officers who continue to review the files and the evidence for the possibility of new leads. And then there are the cases where police haven’t been able to determine the victim’s identity.

These are stories of the families and the police as they seek to learn who killed these victims and why.