John Yamada is a character in Mr. Monk and the Blue Flu. He is an architect who was run down while jaywalking. As it turns out, he was killed by Madam Frost, who killed him because he may have witnessed her killing Allegra Doucet. Madam Frost killed him because she knew the witness was born on February 20th, 1962 in San Francisco, and still lived there. He was not the witness, however. After he died, Madam Frost also killed Diane Truby and Scott Eggers.