Four days after a grenade was thrown at Netanya Mayor Miriam Fierberg's house, officers in the National Headquarters said Sunday that combating violence and intimidation against local officials would be given top priority in 2007 alongside the fight against terror. Combating the phenomenon tops the Operations Division's priority list for the new year, The Jerusalem Post was told Sunday afternoon, while sources within the headquarters said over the weekend that the investigation into the latest case, the grenade thrown at Fierberg, was turned over from the Sharon Subdistrict to the elite Central Investigative Unit of the Central District Police. While officers would not say whether there were significant leads in the investigation, Central District Spokeswoman Ch.-Supt. Shira Lieberman said the case was "viewed as very important and specifically sensitive." Police believe the attack may have been perpetrated by one of the criminal gangs currently under investigation by the CIU. Since the event, Fierberg has been under special protection from police forces. The police's YASAM unit is trained for personal security missions, and Lieberman said there was a special "security package" received by mayors considered to be in physical danger. In the Central District alone, two other mayors are also considered to be in danger and receive special protective services. The district also boasts a rare success rate in getting to the bottom of such cases - in April, a young man was arrested, indicted and convicted for attacking the mayor of Hod Hasharon and that same month, another man was arrested under suspicion of preparing an explosive device to use against Petah Tikva Mayor Yitzhak Ohayon. But even with those incidents, the Central District is still below the national average for mayors between the crosshairs. Throughout the country's six districts, 20 mayors are considered to be in mortal danger. On a national level, one officer said, police have seen "increasing violence against local leaders that has manifested itself in different ways." Police operations, he said, recently have targeted the attempts on mayors' lives through intelligence work and the use of undercover agents. But Lieberman argued that the difficulty in preventing such attacks lay in their unpredictable nature. "It's hard to know who the next attacker will be," he said. "It could be a kiosk owner whose kiosk was issued a closure order, it could be a homeowner who wasn't granted a building permit, a disgruntled pub owner, and thus it's very hard to keep your hand on the pulse of all of those different factors at once. Our ability to deal with these attacks also depends on the levels of cooperation we receive from the mayors themselves." Since he took office in June, Internal Security Minister Avi Dichter has lashed out against these attacks, listing them as one of the major factors in the declining sense of public security in Israel. In August, in the midst of the furor surrounding changes in the security plans for schools, Dichter had tried to distract angry local leaders by talking up his plans to take action against citizens who threaten local politicians. Two months later, he reiterated his message after the home of Nahariya Mayor Jacky Sabag was targeted by criminals throwing stun grenades.