Red-shirt leader Jatuporn Prompan says the man arrested in the Phramongkutklao Hospital bombing deserves to be condemned if guilty, but he expressed scepticism about the seemingly neat preservation of the evidence in the case.
Regardless of what political views anyone held, the person who carried out the bombing at the military hospital deserved condemnation for his cruel and inhumane act, said the head of the United Front for Democracy against Dictatorship (UDD).
Mr Jatuporn said he had closely followed the news about the bombing and the arrest of the suspect on Thursday at his Bangkok home, where bomb-making materials were seized.
Deputy Prime Minister Prawit Wongsuwon said he was certain that authorities had the right man.
Authorities say that Watana Pumret, an electrical engineer who retired from the Electricity Generating Authority of Thailand two years ago, confessed to be responsible for the May 22 bombing at the hospital where 20 people were injured.
Mr Jatuporn said he did not personally know the suspect but questioned why anyone would have kept so much evidence, much of it appearing to be brand-new, in his home.
Authorities claim the suspect had confessed to having been involved in other bombing incidents dating back to 2007. May 22 was the third anniversary of the 2014 military coup that ended months of street protests that had paralysed the elected government of Yingluck Shinawatra.
The UDD leader urged authorities to handle the case in a straightforward manner. For example, he noted reports that a clock featuring the image of ousted former prime minister Thaksin Shinawatra and some red clothes had been been found in the house. These should not be used to conclude that the suspect wanted to take revenge on the military for breaking up earlier red-shirt protests, he said.
Mt Jatuporn made the comments as he and UDD co-leaders Natthawut Saiklur and Tida Tawornseth joined other red-shirts to visit Arisman Pongruangrong and 12 other supporters who were imprisoned at the special Pattaya prison in Chon Buri.
Arisman and the other red-shirts are serving four-year jail terms for their roles in storming the 2009 Asean Summit in Pattaya. They have been behind bars for almost three months as their bail requests have been rejected.