Sandy Springs Police Chief Gene Wilson suddenly resigned Saturday, and Maj. David Bertrand will serve as acting chief while the city looks for someone to permanently fill the job, Mayor Eva Galambos said.

Galambos said city officials "didn't know it was coming" but added Wilson has had "some health problems" that may be the reason he is stepping down.

"He did a fantastic job starting up the department," Galambos said of the department's first and only chief.

The then-new city started providing its own police protection on July 1, 2006. Bertrand, like Wilson, has been with the Sandy Springs Police Department since its infancy.

Bertrand, a recent graduate of the FBI Academy in Quantico, Va., supervised patrol officers and worked in other administrative areas.