Moscow ( CNN ) -- Russian investigators were hunting Thursday for the assassin of a reputed Russian mafia kingpin who was fatally shot by a sniper outside a restaurant in central Moscow . Aslan Usoyan , also known as Granddad Khassan , was the target Wednesday afternoon of what appears to be a contract killing amid a gangland turf war , state media said . A restaurant worker injured in the shooting was in a critical condition Thursday , state-run Itar-Tass news agency reported , after being hit by two bullets . She suffered damage to her spine and lungs , and is on a ventilator , the news agency reported . A doctor told the state-run Russia 24 channel that the 30-year-old woman might not walk again . Russia 's Investigative Committee , which is probing the attack , said the killer had used a VAL assault rifle fitted with a silencer . The weapon is standard issue for military special task force units , according to Itar-Tass . Usoyan , who was in his 70s , suffered a single bullet wound to the neck , the committee said . Two bodyguards who were with Usoyan administered first aid in the restaurant on Povarskaya Street , but their boss later died in the hospital . One bodyguard returned fire in the apparent direction of the shot but had to retreat into the building after coming under further fire from the assassin , the committee said . The assassin fled the scene without being caught . Investigators later found the spot where the killer had waited to take aim , the committee said -- a stairway between the fifth and sixth floors of a nearby building . Six shells were found there , along with a camp chair and piece of fabric . Involved in the criminal underworld since the 1960s , Usoyan had survived at least two previous attempts on his life , one in 1998 and the other in 2010 , state-run RIA Novosti reported . He was involved in gambling , drug trafficking , illegal arms sales and extraction of mineral resources , it said , and controlled organized crime groups in Moscow and across the country . CNN 's Alla Eshchenko and Phil Black in Moscow , and Laura Smith-Spark in London contributed to this report .
NEW : A restaurant worker injured in the shooting may be paralyzed , state media say . Investigators are hunting for the assassin of a reputed Russian mafia kingpin . Aslan Usoyan , also known as Granddad Khassan , was shot at a restaurant , authorities say . The gunman fled and is still on the run.