Yemeni rebels bombed the house of a pro-government tribal chief in the north of the country killing three people, the interior ministry said Saturday. The ministry, in a statement on its Internet website, described Friday's attack against the house of Sheikh Saghir Aziz in Harf Sufyan as an “act of sabotage.” Aziz was not in the house at the time but three of his supporters were killed, it said, adding that authorities had launched an investigation to bring the assailants to justice. The attack was the second in 12 days in Harf Sufyan, in Amran province, allegedly involving Zaidi Shiite rebels. Meanwhile, security sources said that Yemen has arrested four militants over the drive-by killing of a senior intelligence officer, including two suspects that police believe are linked to Al-Qaeda, security sources said Saturday. Two motorcycle gunmen shot dead Colonel Saleh Amtheib Thursday as he relaxed outside his home after lunch. He was the second security officer gunned down in the southern Abyan province in less than a month. Two of those arrested over the attack were previously suspected of belonging to Al-Qaeda, while the others had been unknown to authorities, the sources said. Security forces also confiscated a gun they said was used in the shooting. Authorities had initially been uncertain whom to blame for the killing, the sources said. The officer had participated in the government's battles against Al-Qaeda and also in a separate conflict with armed south Yemen separatists.