Thai police said Thursday that they are examining pictures of Turkish nationals who arrived in the country in the 15 days preceding the attack on the Erawan Shrine in the capital Bangkok. Even after a week since 20 people, mostly foreigners, were killed in the Southeast Asian nation's worst bomb attack, authorities have little clue about the suspects and the motive behind the bombing.

Security analysts and some local police officials have raised the possibility that Uighurs -- a Turkik-speaking Muslim ethnic minority from China's northwest -- may be connected to the Aug. 17 blast at the Hindu shrine. National police spokesman Prawut Thavornsiri reportedly said that police checked arrivals of Turkish nationals who entered Thailand around two weeks before the fatal blast. “More than 20 Turkish people came in during the period," a police source told local media.

Prawut reportedly said that “there are probably more Turkish coming into Thailand than that.”

“We investigated groups which may have come into the country," Prawut said, adding that police have not ruled out any group or nationality. "We are not focused on the nationality but the individual.”

Turkish people see China's treatment of the Uighurs as an important issue as they share a common cultural and religious background.

In July, Thailand deported over 100 Uighurs, who had fled China’s troubled western Xinjiang region, to China -- a move that prompted widespread condemnation from international rights groups and sparked a mob attack on the Thai consulate in Turkey.

Anthony Davis, a Bangkok-based security analyst with IHS-Jane's, told Reuters that the attack may have been carried out by members of a right-wing Turkish organization known as the Grey Wolves.

"The Uighur cause is something they've latched onto in a big way," Davis reportedly said, adding that the Grey Wolves were "at the front of the queue" during protests over the deportation of Uighurs.

Authorities, however, have been trying to downplay speculation of the involvement of Grey Wolves.

The main evidence that police have is security camera footage that showed a man in a yellow T-shirt, allegedly planting a bomb in a backpack at the Erawan Shrine, one of Bangkok’s famous tourist attractions. Police believe him to be the prime suspect. They have released his sketch and issued an arrest warrant against him last week.