With law enforcement agencies across the nation already on high alert following a deadly attack on police in Louisiana, Suffolk County police said they were investigating a graffiti incident in Lake Grove, where someone wrote: “Kill All Cops.”

Police declined to speak directly about the phrase, which was found spray painted on a utility pole along Middle Country Road near Parsnip Road in Lake Grove on Sunday.

The incident was reported in a 911 call.

The scene is just east of the Smith Haven Mall.

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Police released a statement Sunday, with department spokesman Justin Meyers saying: “We received a 911 call reporting graffiti in Middle Island and we are looking into it.”

Police said Monday they would have no other comment at this time.

The graffiti appeared on the same day three officers were killed in an attack in Baton Rouge, where authorities said a former Marine dressed in black and carrying extra ammunition shot and killed two police officers and a sheriff’s deputy.

Law enforcement officers on Long Island and across the United States have been on heightened alert after five officers were shot and killed in Dallas on July 7, which followed separate incidents that saw two black men fatally shot by police in Baton Rouge and in Falcon Heights, Minnesota.