Police on Tuesday evening arrested a Petah Tikva man who threatened Yesh Atid leader Yair Lapid on his Facebook page. The man was set to undergo interrogation Wednesday before being taken to court for a remand hearing.

Drawing on the lore associated with the upcoming Jewish holiday of Purim, the man wrote that “we should hang Lapid and our leftist enemies just like we hanged Haman and his sons.”

According to tradition, Purim marks the salvation of the Jews of ancient Persia. Haman was the royal adviser who, in the Old Testament Book of Esther, was hanged along with his 10 sons after his plan to slaughter the Persian Jewish community was miraculously foiled.

“If people like [Lapid] join our government, we should remove the Star of David [from the Israeli flag] and replace it with a swastika, which better characterizes this country,” the man wrote.

An official police statement described the incident as “grave” and said that police were treating it with the utmost seriousness. “Things that were written represent a serious threat,” the statement said.