BALTIMORE — Baltimore police say four people were killed and six wounded in Labor Day shootings.

Police spokesman Anthony Guglielmi says investigators are still working to determine if any of the shootings are related, which he said was very possible. Guglielmi says police are also stepping up patrols in the areas where the shootings occurred because of the possibility of retaliation.

The spokesman says the identities of the victims were not immediately released pending notification of relatives. Three of the incidents were double shootings and the rest involved single victims.

Guglielmi says all of the victims are believed to have been targeted by the gunmen involved in the shootings, adding that all had prior contact with law enforcement.