Xinjiang police are looking for 10 family members of an alleged assailant killed in Wednesday's deadly bomb and knife attack in Urumqi.
In a notice issued on Friday, the police offered a reward of up to 100,000 yuan (HK$126,000) for information on the attack that took place just as President Xi Jinping wrapped up his tour of the restive region.
It urged all units to conduct "thorough investigations" for more information about one of the suspects, who has yet to be identified.
Police said earlier that two assailants set off bombs after launching a frenzied knife attack at Urumqi South railway station, killing themselves and one bystander, and injuring 79 others. Xinjiang Daily yesterday said it only took four seconds for the suspects to detonate the bombs.
The name of the other assailant has not been disclosed, but police released photos of the suspects to relevant authorities, one set taken at the scene of the blast and the other taken of the suspects' corpses, according to a copy of police orders obtained by the Sunday Morning Post.
Police ordered authorities to use all resources, including "secretive forces," to conduct a thorough investigation "by all means" into the assailants and other suspects. Checks on guests at hotels, internet cafes and public baths are to be stepped up.
Police from Urumqi's Saybagh district also offered a reward for information in an official weibo post yesterday afternoon. The post showed pictures, apparently taken by surveillance cameras, of two suspects in similar clothing and carrying similar suitcases before the attack.
In a separate notice, local police demanded all authorities look for the 10 family members and other relatives of the alleged assailant. They include his 69-year-old father, 77-year-old father-in-law, his wife, brothers and cousins.
Two officers with the Urumqi public security bureau confirmed they had issued the orders, but said they may be removed soon after further information had come to light.
Watch: Security tightened after Urumqi railway station attack
Raffaello Pantucci, a senior research fellow with the London-based Royal United Services Institute, said the assailants were demonstrating their frustration directly towards the top leadership, and that the attack reflected weaknesses in intelligence-gathering. A heavy security clampdown in the region was expected, he added.
"I think for a failure like this, the leaders will be embarrassed and they will want to do something to remedy that," he said.
In a sign that authorities are widening their probe into potential future bomb blasts, security authorities issued another order calling for the arrest of two Uygurs allegedly belonging to a bomb-making syndicate. The suspects, both from Kucha in southern Xinjiang, are allegedly active in Urumqi and the Bayingolin Mongol Autonomous Prefecture.
However, an officer at the security agency issuing the order insisted there was no link between the two suspects and Wednesday's attacks.
Urumqi was rocked by ethnic violence in July 2009, when at least 197 people killed.