Commandos arrest Pakistani arson suspect Abdul Rehman on Nana Road in Bangkok on Friday evening. (Photo by Wassayos Ngamkham)

Police arrested a 46-year-old Pakistani man in Bangkok on Friday evening for alleged involvement in the world's sixth deadliest arson that killed 259 people in Pakistan in 2012.

Abdul Rehman was arrested in Room 405 of the Royal Garden Home hotel on Sukhumvit Soi 3 (Nana) following a raid by commandos from the Crime Suppression Division (CSD) and Interpol officers.

Police found the man alone in the room and did not see anything illegal there. They collected clothes, documents and cigarette butts for further examination.

Acting CSD commander Suthin Sapphuang, who led the raid, said the arrest was connected to a fire at the Ali Enterprises textile factory in Karachi on Sept 11, 2012, when 259 people were killed and 50 others were seriously injured.

Pakistani authorities concluded the attack was arson and linked it to the suspect. An anti-terrorism court in Karachi issued a warrant for Mr Rehman's arrest on Sept 16 this year, and Pakistani authorities later learned that he had fled to Thailand, Pol Maj Suthin said.

Pol Lt Col Chai Sa-nguansin, a deputy superintendent of Interpol, said the suspect was alleged to be a member of a large criminal organisation in Pakistan, which extorted money from local businesses.

Before the fire, it is alleged, the group had demanded the equivalent of 7 million baht from the owner of the textile factory. When the owner refused, the factory was torched. It was the sixth worst arson in history, Pol Lt Col Chai said.

The German clothing retailer KiK, the main customer of the plant, paid US$1 million in compensation immediately after the fire to help victims and their families. In September this year, it agreed to pay an additional $5.15 million in an agreement negotiated under the auspices of the International Labour Organization.