(AP) — The FBI has reached a milestone in its 63-year-old program of pursuing its “Ten Most Wanted Fugitives.”

It has added the 499th and 500th names of fugitives to have appeared over the years on its regularly updated list.

The FBI says citizen cooperation has led to 155 of the fugitives being apprehended or their bodies found.

The two new additions are Jose Manuel Garcia Guevara, who allegedly murdered a 26-year-old woman in the presence of her 4-year-old stepson in Lake Charles, La., in 2008; and Walter Lee Williams, a former California professor wanted for the alleged sexual exploitation of children and traveling abroad to engage in illicit sex acts with children.

Guevara is believed to be in Mexico. Williams has lived in Palm Springs, Calif., and has traveled extensively in the Philippines and has reportedly lived in Indonesia, Polynesia and Thailand.