The sighting came only months after officials staged a celebration in April marking five years of being free of the tree-killing bug, the Chicago Tribune reported Saturday.

Scientists told the newspaper this week that a single beetle was found in the parking lot of a Deerfield, Ill., shopping mall, and that it bore the distinctive marks of the troublesome insect.

They said an investigation by specialists from the U.S. and Illinois departments of agriculture will begin Monday when the experts will try to determine if the Deerfield beetle is a survivor of earlier eradication efforts or if it signals a new infestation, the Tribune reported.