After two consecutive terrorist attacks involving bulldozers, Jerusalem police on Wednesday heightened security at major building sites in an effort to prevent further copycat attacks. The new measures include spot checks of Arab workers from east Jerusalem and a review of workers' criminal records, Jerusalem police chief Cmdr. Aharon Franco said. The heightened police presence, which was clearly evident at construction sites throughout the capital, came a day after 22-year-old Ghassan Abu Tir from east Jerusalem's Umm Tuba neighborhood used his bulldozer to wound more than a dozen people on King David Street before being killed himself, and three weeks to the day after Husam Taysir Dwayat from the city's Sur Bahir neighborhood used a bulldozer to kill three people and wound three dozen across town on Jaffa Road. Security officials said that the heightened measures had already gotten underway on a smaller scale after the first bulldozer attack. The law bars most private employers - including construction companies - from checking employees' criminal records, but police can do so. Both bulldozer attackers had criminal records - Dwayat served a two-year sentence for raping his former Jewish girlfriend and Abu Tir had a criminal record for drugs and theft - but security officials conceded that such offenses, even had they been known, would not have been enough to prevent them from getting their jobs as bulldozer drivers. Police could be seen walking through dust-choked construction sites for the city's light rail system on Wednesday, questioning Arab workers and checking their IDs. At several work sites, the ubiquitous bulldozers - which have now been dubbed "killdozers" - were being driven by Jews, with Arabs given other tasks. "Those [people] who did what they did sure did not think about us," said a laborer from east Jerusalem who would only give his first name, Muhammad. "They are ruining our lives." At the site of Tuesday's attack on King David Street, work continued Wednesday at the construction project behind the YMCA, where police said the attacker had been employed. Adjacent to the King David Hotel, George Washington Street, from where Abu Tir, drove his bulldozer onto King David Street, showed almost no signs of the carnage that he had wrought a day earlier, save for the deep marks on King David Street. One bulldozer - similar to that used in the attack - was seen working in the area. "We should not judge people because of a few crazies," said Danny Ayash, manager of the Little Italy restaurant just up the street. Like almost every eatery in the capital, Ayash employs Arabs from east Jerusalem. He said that his Arab workers, who had all come with recommendations, had worked for him for years, with the newest one hired eight years ago. "They feel very bad about what has happened, especially the old-timers, and they are afraid they will lose their livelihood," Ayash said. "Maybe tomorrow they will tell me not to come to work anymore," said a chef at the restaurant from east Jerusalem who would only give his first name, Omar. "Those who carried out these attacks are not thinking about themselves or anyone else," the 45-year-old father of five said. As Israel weighs the pros and cons of demolishing - or at least sealing - the homes of Arab terrorists who live in east Jerusalem, and other punitive measures, most of the city's 250,000 Arabs continue to depend on income from jobs in west Jerusalem. Their Israeli employers are often no less eager to employ them. "What we are seeing are the logical results of a faulty Israeli policy," said Mordechai, who works at a Judaica shop on King David Street, next to the attack site. "If we paid Jews normal salaries to do the work, the whole situation would be different," he said.