Deputy National Police Chief Phanupong Singhara Na Ayutthaya called a meeting of investigators late Tuesday focusing on the investigation.
Pol Gen Phanupong said the homemade bomb was in an open black bag placed on a traffic island. The explosive device was an iron pipe 12cm in diametre by 18cm long, wrapped in tape, with a digital clock, electrical circuit, batteries and small pieces of metal and broken glass. The clock was set at the number 1 which could be 1am or 1pm.
After the bomb squad defused the explosive at 3.30pm using a high-pressure watergun, they found that its circuit was incomplete. Police believe that the device was aimed to cause disturbance or threaten the public.
If the bomb was functional, police said, its blast radius could be10 metres.
A guard at a nearby parking lot said he began work at 6am and noticed the open-bag at around 9am but was unaware there was a bomb until a motorcyclist looked inside and informed the police.
Gen Phanupong said that Deputy Prime Minister Pol Capt Chalerm Yubumrung and National Police Chief Pol Gen Prewpan Dhamapong consider the incident as a serious case.
He said the police will reinspect the scene, check the CCTV footage and question witnesses to seek clues lead to find a suspect.