BAGHDAD, Aug. 3 (Xinhua) -- Unidentified gunmen assassinated an aide of top Shiite cleric Grand Ayatollah Ali al-Sistani near his home in the city of Najaf south of Baghdad on Thursday, local police source said on Friday.
"Three gunmen in a vehicle shot dead Sheikh Fadel al-Aqel, a deputy of Sistani, in the neighborhood of al-Milad in Najaf City at about 10:00 p.m. (1800 GMT) on Thursday," the source told Xinhua on condition of anonymity.
The incident, which is under investigation, is the fourth of such kind in two months, the source said.
Two weeks ago, Sheikh Abdullah Falak, an aide of Sistani, who was in charge of financial duties in the cleric's office, was also stabbed to death inside his office in Najaf.
Falak's assassination set off questions among Iraqis as the place where he was killed was only 50 meters away from Sistani's heavily-guarded residence.
Another aide, Kadhem al-Baderi, in charge of protecting the most sacred Imam Ali Shrine and Sistani himself, was shot dead by gunmen few days ago outside the city.
A third of Sistani's aides, Sheikh Rahim al-Hassnawi, was assassinated in front of his home in the town of al-Mishkhab, south of Najaf.