BOGOTA, Oct 13 — Luis Alfredo Garavito, Colombia’s deadliest serial killer and one of the worst in the world, died Thursday while serving time for abusing, torturing and murdering at least 170 boys aged eight to 16, the country’s prison authority said.

Known as "The Beast” or "The Monster of Genova,” after his native town, Garavito died at the age of 66 in a clinic from "multiple conditions,” the INPEC penitentiary authority said in a statement.

He had been behind bars since 1999.

Posing as a travelling salesman, a monk, a disabled or homeless person and even an aid worker, Garavito was able to enter schools to find his victims, investigators said at the time.

The murders took place after he led the boys to isolated areas, luring them with food and drink, and assaulting them when they tired of walking.

He had kept a record of his victims in a small notebook.

The biggest criminal investigation in Colombian history at the time was launched in October 1998 when police realized they were dealing with a serial killer after finding the bodies of 36 murdered children in the town of Pereira.

A year later, authorities announced they had found the man responsible.

Garavito tortured and mutilated his victims before slitting their throats, prosecutors said.

He confessed to his crimes and was sentenced in 2000 to a total of 835 years in prison. The maximum sentence that can be served in Colombia is 40 years.

Garavito had since been diagnosed with cancer in an eye and leukaemia.

He had also confessed to crimes in Venezuela and Ecuador, where he was sentenced to 22 years in prison in absentia. — AFP