Police believe haredi extremists covered monuments at the Yad Vashem Holocaust Memorial and Museum in Jerusalem with hateful anti-Zionist slogans early on Monday morning.One spray-painted slogan said, “If Hitler hadn’t existed, the Zionists would have invented him.”Jerusalem Post staff contributed to this article.“Thanks Hitler for the wonderful Holocaust you organized for us! Only because of you we received a state,” read another, while a third slogan was, “Jews, wake up, the evil regime does not protect us, it only endangers us.”Ten graffiti slogans were spray-painted in large black letters concentrated in the Warsaw Ghetto Square and the Deportees Memorial next to the cattle car.One of the graffiti slogans was signed “World Haredi Jewry.” That, as well as the content of the graffiti, led police to believe that the vandalism was carried out by extremist anti-Zionist factions within the haredi community, said Jerusalem police spokesman Shmuel Ben- Ruby.Yad Vashem chairman Avner Shalev said the graffiti “crossed a red line,” and that it was the worst thing he had seen in his career.“Throughout all of Jewish society and Israeli society [Yad Vashem is] a symbol of unity, of tolerance, of values and openness, of discourse and dialogue among all types of ideas,” said Shalev. He added that the museum had not experienced any type of vandalism in recent years, and certainly nothing on this scale.The main plaza of the museum, the Warsaw Ghetto courtyard, was covered with slogans that stretched more than twometers tall and five-meters wide, encompassing entire walls surrounding the memorial statue in the front of the square. The vandals most likely entered the museum grounds from the Jerusalem forest, which surrounds the building.Shalev said that although the museum retains a private security force, the 200-dunam (20- hectare) campus is so large that anyone who truly wanted to vandalize the museum would find a way to slip into the area. Footage from the museum’s security cameras was immediately given to the police.Shalev also said that the Hebrew graffiti appeared to be from at least two people because the handwriting was different.Jerusalem Police chief Cmdr. Nisso Shaham called the incident “shocking” and said, “We must investigate and deal quickly with these despicable acts... in which one of Israel’s important symbols was attacked.”Education Minister Gideon Sa’ar said that the vandals desecrated the museum with the “intention of offending public sensibilities.”The museum was not closed to visitors except for the vandalized area, and around 3,000 people were expected to visit on Monday.Staff from Yad Vashem milled around the courtyard.“It’s difficult to stand here,” said one worker, as she looked at the graffiti.