As police searched for a man they believe is responsible for a blast that killed at least 20 people and injured 140 others on Monday, a second explosion hit Bangkok on Tuesday.
The second explosion was not deadly. According to the Bangkok Post, someone threw a pipe bomb off a bridge. The bomb hit a pillar and detonated, "sending up a large plume of water."
The blast on Monday was caused by an improvised explosive device. The Associated Press reports that police released security video of a man wearing a yellow shirt and who they say placed the device in a bustling area of town.
"Police Lt. Gen. Prawut Thavornsiri earlier released several photos of the man, with and without the backpack, that were apparently taken from closed-circuit video at the Erawan Shrine, before the bomb exploded near a busy intersection. ...
"Monday's blast, from an improvised explosive device, took place around 7 p.m. local time near the shrine, a Hindu religious site popular with Thai Buddhists and Chinese tourists. It is located in a bustling area. Thailand's prime minister vowed to track down those responsible.
"Prime Minister Prayuth Chan-ocha said 'some suspects' were seen in security-camera footage, and described the incident as the worst attack in the country's history."
The BBC reports that neither the suspects nor their motives have been identified. It says:
"There is no shortage of potential suspects — people might wonder if it was the Muslim insurgency fighting for an independent state in the deep south. Lots of bombs go off there, but the insurgents have never perpetrated an attack outside their own area, so this would be an entire change in tactics.
"People also look at the recent political violence and wonder if factions who lost out might have been involved.
"It will be some time before the government gives some idea of what we should be looking for."