Bangkok blast 'mastermind' left Dhaka on August 30

A man, who Thai police believe masterminded deadly Bangkok bombing and fled to Bangladesh the day before the attack, left Dhaka on Aug 30, the Bangladesh embassy in Bangkok has said.

The Bangkok mission on Friday said their records showed the alleged mastermind had been issued "a single entry tourist visa" on the basis of "all valid travel documents" in early August and entered Bangladesh on August 16, bdnews24 reported on Saturday.

The Erawan Shrine bomb blasts took place on the following day which killed 20 people and injured over 150 others.

"By the time Bangladesh authorities received information from Bangkok Law Enforcement Agencies, the alleged person had already left Bangladesh on August 30," the Bangladesh mission said in a statement.

The statement said Bangladesh would be "working closely with Thailand in tracing all available information" about the alleged plotter's two weeks' stay in Bangladesh.

"The law enforcing agencies in Bangladesh are currently investigating the case and would share all relevant information with Thai authorities and all other concerned countries and agencies including the InterPol."

Since the bomb blast in August, the embassy said it had put "high security alert" on its tourist visa regime for travellers from Thailand to Bangladesh.

It said it had also given all information regarding the individual to relevant Bangladesh and Thai authorities.

The alleged mastermind was travelling on a Chinese passport, Bangkok officials earlier this week.

The Bangladesh mission said the ambassador was "in close touch" with the Thai foreign ministry, law-enforcing agencies and media.

The relevant agencies of the two countries are also exchanging information on the case, it added.