Federal prosecutors in Utah are moving to dismiss a case alleging a 3-year-old boy was abused on a plane.

Prosecutors said in court documents filed this week that that there's insufficient evidence against 48-year-old Kevin C. Matthews of Illinois.

Melodie Rydalch, a spokeswoman for the U.S. Attorney's Office for Utah, tells the Desert News of Salt Lake City that dismissing the charge of abusive sexual contact is the right thing to do.

Defense attorney Susanne Gustin declined immediate comment Friday.

Investigators said in a complaint filed in March that the boy's family was separated because they were flying standby on the flight from Chicago to San Diego with a layover in Salt Lake City. Charging documents said the boy was seated near Matthews and nearby passengers reported the abuse allegation to flight attendants.