Alaska serial killer Israel Keyes has been linked to a possible 11 murders and might even be responsible for deaths in other countries, federal agents revealed, according to CNN. Keyes committed suicide in December with a razor that was given to him by prison officials, nearly nine months after he murdered Starbucks barista Samantha Koeing.

Keyes’ murderous rampage might have extended outside of the U.S., according to the FBI’s statement. "Keyes traveled internationally, and it is unknown if he committed any homicides while outside of the United States.” The serial killer lived in upstate New York for a time and "reported several trips to Montreal in which he sought out prostitutes.” He then drove through western Canada while making his way to Alaska, where he lived until his arrest.

An interactive map of Keyes’ location on specific dates pinpoints where the killer was. On March 1, 2005, for instance, he was on a "Day canoe trip to unspecified location.” The map shows a mountainous region of Washington east of Seattle, the news site added.

"If we have a missing person identified in a particular area, we work closely with that local police department to either connect the person to Keyes or not," Jolene Goeden, FBI special agent in Anchorage, said in a statement quoted by CNN. "We have his DNA."

Right before his death, the 34-year-old Keyes reportedly admitted to at least seven more slayings, ranging from Vermont to Washington state. A statement issued Monday by the FBI office in Anchorage said Keyes killed at least another three victims before his death:

--a pale-skinned woman, who was in an older car, “possibly having a wealthy grandmother”

--another where the victim was positioned to look like the death was an accident

--one “in Texas or a surrounding state,” which he had denied committing before he died.

Keyes killed himself by slitting his wrists and then strangling himself with bedding. He left behind a four-page suicide note that didn’t express a shred of remorse. Investigators said he had "a meticulous and organized approach to his crimes" and he was described as a “murder addict.”