Police on Thursday opened an investigation after a threatening note and bullet were found on the windshield of a car belonging to Avi Gruber, the mayor of Ramat Hasharon.

On a sheet of paper was scrawled the short message “Price tag coming soon.”

So-called “price tag” hate crime attacks, usually arson and graffiti, have been carried out by right-wing Jewish extremists as revenge against Arab, Christian and IDF, ostensibly in protest of Israeli policies they deem unfavorable.

The note and bullet were found in a plastic bag on Gruber’s car earlier on Thursday morning. The “price tag” slogan was also found daubed on a wall of the apartment complex where Gruber lives in the central Israel town.

Gruber filed a complaint with police.

Hebrew media reported that municipal officials speculated the threats were made because Gruber did not offer separate seating for religious men and women at this week’s municipal Independence Day events, and over his campaign to close an illegal yeshiva in the city.

Mayoral candidate, Avi Grober, seen after the Ramat HaSharon Mayoral elections, on January 13, 2016. (Flash90)

Avi Grober after the Ramat Hasharon mayoral elections, January 13, 2016. (Flash90)

Times of Israel staff contributed to this report.