A 69-year-old man has been charged with trying to extort $10,000 from the FBI in exchange for helping avert a purported plot to contaminate four public water supplies in Kansas and Missouri.

U.S. Attorney Tammy Dickinson announced the charges Friday against Manuel Garcia of Kansas City, who was arrested and placed in federal custody pending a detention hearing.

Dickinson says there was no evidence of a credible threat to the water supplies in St. Louis, Kansas City, Missouri; Topeka and Wichita, Kansas.

Prosecutors allege Garcia called the FBI and other agencies this month claiming two acquaintances planned to put some kind of dangerous chemical into the communities’ water supplies. Investigators say Garcia offered to try to locate the two men in exchange for $10,000 and a grant of immunity.