(CNN) -- A suspected serial killer has killed for the last time. Authorities say Israel Keyes, who was arrested and charged in the killing of an Alaskan barista, killed himself while in custody. Before committing suicide on Sunday, Keyes confessed to at least seven other slayings, according to the FBI field office in Anchorage, Alaska, which on Monday asked for the public's help with tracing Keyes' travels over the years in the hopes of identifying any additional victims. He crisscrossed the country, and authorities may never know how many he killed. "Based upon investigation conducted following his arrest in March 2012, Israel Keyes is believed to have committed multiple kidnappings and murders across the country between 2001 and March 2012," the office said in a statement. "Keyes described significant planning and preparation for his murders, reflecting a meticulous and organized approach to his crimes."
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Israel Keyes committed suicide while in custody on murder charges, officials say
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He was charged in the death of 18-year-old Samantha Koenig, an Alaskan barista
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He is said to have confessed to multiple murders and did not know any of his victims
After @placeholder made the coffee, Keyes brandished a gun forced himself into the coffee stand and bound the 18-year-old woman with zip ties.