Healdsburg police are investigating an early Tuesday graffiti spree that targeted 19 spots in the downtown area.

It's unclear if the graffiti was gang related, police said.

Of the locations that were hit, six were on Healdsburg Avenue, six on Center Street, two on Mill Street and two were on Matheson Street.

The graffiti was first discovered at 1 a.m. and continued through the early morning hours, even as police investigated some of the locations.

Police are still searching for the suspect or suspects responsible.