( 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 . '' Investigators are continuing to investigate those crimes , though they say Keyes confessed to killing at least seven other people besides the barista : two in Vermont , four in Washington state , and one somewhere on the East Coast , disposing of the body in New York . Keyes did not know any of his victims , the FBI said , but looked for them at remote locations like parks , campgrounds and cemeteries . He is said to have buried supplies he planned to use in future crimes , and investigators recovered two caches , one in Eagle River , Alaska , and one near Blake Falls Reservoir in New York . They contained weapons and items used to dispose of bodies , the FBI said . Keyes allegedly confessed to killing Bill and Lorraine Currier of Essex Junction , Vermont . He flew into Chicago , rented a car and drove across several states before arriving there , the FBI said . He is then thought to have traveled around the East Coast before returning to Chicago and then Alaska , where he had lived since 2007 . Prior to that , he lived in Washington state , where he confessed to killing four people , the FBI said . He is likewise alleged to have admitted to killing another person , somewhere on the East Coast , in 2009 . The identities of those five victims were not released . Finally , Keyes was accused and charged in the death of 18-year-old Samantha Koenig , the Alaskan barista . She was last seen on February 1 being led away by a man from the parking lot of the coffee stand where she worked . Her body was found in a lake north of Anchorage . Authorities in Anchorage released a chilling account of the killing of Koenig in part to `` help investigations of other murders committed by Israel Keyes . '' Keyes had planned to commit a kidnapping at Koenig 's coffee stand even though he did not know her , according to the joint statement by local and federal authorities in Alaska . He approached near closing time on February 1 , wearing a mask and ordered coffee . After Koenig made the coffee , Keyes brandished a gun forced himself into the coffee stand and bound the 18-year-old woman with zip ties . She tried to escape , was unsuccessful and he took her to his truck . `` Keyes drove around town , explaining to Samantha that this was a kidnapping for ransom , '' the statement said . He killed her at his home , hid the body in a shed and then went on a cruise he had been planning . He returned on February 17 . `` He went into the shed and retrieved Samantha 's body , taking steps to make it appear that she was still alive , and took a Polaroid picture of her tied up , '' the statement said . He sent the picture to girl 's family members using her cell phone . He demanded $ 30,000 be sent to an account associated with an ATM card he had stolen from her . The young barista 's family was able to raise the money from donations and sent it . Authorities arrested Keyes after he made withdrawals of that money . But not until the alleged serial killer made withdrawals in Anchorage , Arizona , New Mexico , and Texas .
Israel Keyes committed suicide while in custody on murder charges , officials say . The Associated Press contributed to this report. He is said to have confessed to multiple murders and did not know any of his victims .