Joachim Kroll (April 17, 1933 - July 1, 1991) was a German serial killer and cannibal. He was known as the Ruhr Cannibal (Ruhrkannibale), and the Duisburg Man-Eater (Duisburger Menschenfresser). He was convicted of eight murders but confessed to a total of thirteen.

Born as the son of a miner in Hindenburg, a town in Upper Silesia (then Germany, now Poland), Kroll grew up as the last of eight children. He was a weakling and had been a bedwetter since this time and got a minimal education. (Later the psychiatrists discovered that he had an intelligence quotient of 76).

After the end of the war, Kroll's family relocated to North Rhine-Westphalia. In 1955, living with his father in Bottrop, he began to murder after the death of his mother. Around 1960 Kroll came to Duisburg, to work as a toilet server for Mannesmann . After this he worked for Thyssen Industries and went to Laar, a district of Duisburg. In this time he had begun to murder again.

On July 3, 1976, forty-three-year-old Kroll was arrested after kidnapping and killing a four-year-old girl named Marion Ketter. As officers went from house to house, a neighbor approached the police saying that the waste-pipe in his apartment building had blocked up, and when he had asked his neighbor, Joachim Kroll, if he knew what was blocking the pipe, Kroll had simply replied; "Guts." From this report, the police went up to Kroll's apartment and found the body of the Ketter girl cut up: some parts were in the fridge, a hand was cooking in a pan of boiling water and the intestines were stuffed down the waste-pipe.

Kroll was immediately arrested. He admitted killing Marion Ketter and gave details of twelve other murders and one attempted murder over the last two decades. They were:

• February 8, 1955 - Irmgard Strehl, 19, raped and stabbed to death. Her disemboweled body was found in a barn in Lüdinghausen .
• June 16. 1959 - Klara Frieda Tesmer, 24, murdered in Rheinwiesen .
• July 26, 1959 - Manuela Knodt, 16, raped and strangled in the City Park of Essen. Slices of flesh were carved from her buttocks and thighs.
• 1962 - Barbara Bruder, 12, abducted in Burscheid. Her body has never been found.
• April 23, 1962 - Petra Giese, 13, raped and strangled in Dinslaken-Brückhausen
• June 1962 - Monika Tafel, 13, killed in Walsum , slices of flesh carved from her buttocks.
• August 22, 1965 - Hermann Schmitz and his girlfriend Marion were attacked as they sat in a car in a lover's lane in Grossenbaum-Duisburg . Hermann - Kroll's only male victim - was killed but Marion escaped.
• September 1966 - Ursula Rohling, strangled near Duisburg. Her boyfriend committed suicide after being falsely accused of the crime.
• December 22, 1966 - Ilona Harke, aged 5, raped and drowned in a ditch in Wuppertal.
• July 12, 1969 - Maria Hettgen, 10, raped and strangled in Baldeneysee in Essen.
• May 21, 1970 - Jutta Rahn, 13, strangled walking from a train station to her home.
• 1976 - Karin Toepfer, raped and strangled in Dinslaken-Voerde .

Kroll said that he often sliced portions of flesh from the victims to cook and eat, claiming that he did this to save on grocery bills. In custody, he believed that he was going to get a simple operation to cure him of his homicidal urges and then be released. Instead he was charged with eight murders and one attempted murder and, in April 1982, after a 151-day trial, he was convicted on all counts and given nine life sentences.

He died in prison of a heart-attack in 1991 in the prison of Rheinbach , near Bonn.