BANGKOK — Thai authorities on Friday cast a wider net in the search for the perpetrators of the Aug. 17 bombing in Bangkok that killed 20 people, asking China to check whether a prime suspect had fled there.

Prime Minister Prayuth Chan-ocha said Friday that he did not know whether China would hand over the suspect if or when he was arrested. Police have suggested a man carrying a Chinese passport in the name Abudureheman Abudusataer may have directed the bombing of the Erawan Shrine.

The man, also known by the nickname Izan or Ishan, reportedly left Thailand on Aug. 16 for Bangladesh and then China.

However, police spokesman Prawut Thavornsiri quoted Bangladesh’s ambassador as saying that the suspect left Bangladesh on Aug. 30 and was supposed to transit in Delhi on his way to China but never got to his final destination. The envoy, Saida Muna Tasneem, told police that the suspect obtained a visa for Bangladesh in Bangkok.