Francillon was last seen at the Broad Acres Swap Meet in North Las Vegas, Nevada on August 2, 1986. He has never been heard from again.

Francillon lived with his mother, Amy Luster, and stepfather, Lee Luster, at the time of his disappearance. His biological father, Jean Pierre, was Amy's former boyfriend. The Lusters were charged with felony child abuse in December 1985; they allegedly beat Francillon and caused 30 to 40 welts on his body. They were awaiting trial in that case when the child disappeared. Amy and Lee told the police they'd taken the boy to the swap meet and lost track of him. They asked authorities not to publicize his disappearance or distribute photographs because they didn't want the media to sensationalize it. A month later, they planned to sell some of Francillon's toys at a garage sale to finance a trip to Seattle, Washington. They canceled the sale after it was reported in the local news. In December 1986, Lee and Amy were charged with perjury. Authorities stated they had lied about their backgrounds and where they had lived and worked.

The Lusters suggested Jean might have been involved in Francillon's disappearance. Investigators located him in Haiti about two and a half months later and searched his apartment, but found no trace of Francillon. Jean then traveled to Nevada, took a lie detector test and passed. He was ruled out as a suspect. Amy and Lee are considered suspects in the child's case, but they have never been charged in connection with it. They moved to Florida about eleven months after Francillon disappeared. They stated they still believed Jean had taken Francillon, and that the reason they moved to Florida was to be closer to Haiti, where they believed he was.

Few details are available in Francillon's case. It is classified as a non-family abduction.