May 9 is the 129th day of the year (130th in leap years). There are 236 days remaining.

• 1914 — János Rumpf died.
• 1938 — Carroll Cole is born.
• 1939 — Ramiro Artieda is apprehended.
• 1949 — Arthur Ream is born.
• 1950 — Lorenzo Gilyard is born.
• 1952 — Stanley Buckowski died.
• 1956 — Wayne Henley is born.
• 1967 — Tammie Liles (victim) is born.
• 1967 — Christopher Lovrien is born.
• 1978 — Warren Forrest's victim, Gloria Nadine Knutson, is found.
• 1982 — Margaret J. Miller is allegedly murdered by Lorenzo Gilyard (suspected victim).
• 1983 — Larry Eyler's victim, Daniel Scott Mcneive and Jimmy T. Roberts, are found.
• 1984 — Robert Hansen's victim, Lisa Futrell, is found.
• 1987 — Lee Choon-jae's victim, Park Eun-joo, is found.
• 1993 — Leah Evans is murdered by Joel Rifkin.
• 2004 — Kim Hyun-jin is murdered by Jeong Nam-gyu.
• 2012 — Zhang Yongming is apprehended.