The Cleveland Torso Murderer (also known as the Mad Butcher of Kingsbury Run) was an unidentified serial killer

Serial killer

A serial killer, as typically defined, is an individual who has murdered three or more people over a period of more than a month, with down time between the murders, and whose motivation for killing is usually based on psychological gratification...

 who killed and dismembered at least 12 victims in the Cleveland, Ohio

Cleveland, Ohio

Cleveland is a city in the U.S. state of Ohio and is the county seat of Cuyahoga County, the most populous county in the state. The city is located in northeastern Ohio on the southern shore of Lake Erie, approximately west of the Pennsylvania border...

 area in the 1930s.
The official number of murders credited to the Cleveland Torso Murderer is 12, although recent research has shown there may have been more. The 12 victims were killed between 1935 and 1938, but some, including lead Cleveland Detective Peter Merylo, believe that there may have been as many or more than 40 victims in the Cleveland, Pittsburgh

Pittsburgh, Pennsylvania

Pittsburgh is the second-largest city in the US Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States...

, and Youngstown, Ohio

Youngstown, Ohio

Youngstown is a city in the U.S. state of Ohio and the county seat of Mahoning County; it also extends into Trumbull County. The municipality is situated on the Mahoning River, approximately southeast of Cleveland and northwest of Pittsburgh, Pennsylvania...

 area between the 1920s and 1950s.