As there are many unsolved murders this cannot be known.
use fingerprints
845
not enough evidence i guess
The unsolved 'Jack the Ripper' murders.
Unsolved Mysteries - 1987 The Two Mary murders 13-6 was released on: USA: 17 June 2002
20
As of 2020, the FBI estimates there are around 250,000 unsolved murders in the United States. However, this number may vary depending on the sources and definitions used for "unsolved murders."
Locations of killings: Washington, Colarado, Utah, Oregon, Idaho and Florida. Ages: 12-26 Ted Bundy confessed to the murders of many females before his execution in 1989 but there are many that still remain unsolved. There have been more murders that could possibly been linked to Ted.
Detroit, Michigan has one of the highest rates of unsolved murders in the US, with many cases remaining open due to a combination of factors such as limited resources, distrust of law enforcement, and the nature of the crimes.
The FBI reports that for 2008 the total for the State of Florida was 1,116 murders and non-negligent manslaughter committed.
Here in India, I can say, more than 100 million of cases are still pending and if you ask every year, it's around 10 million. This all happens just because of lengthy, critical legal process and corruption in judiciary. There are about 150 - 200 unsolved murders in New York City every single year, according to "the restless sleep", and now there are over 9,082 unsolved murders in New York since 1985