THE explosion at Phramongkutklao Hospital on Monday, which left more than 20 people injured, has drawn widespread condemnation as the perpetrators targeted patients and innocent people.

The explosion occurred inside the Wongsuwan Room of the military-run hospital on the third anniversary of the coup on May 22, 2014, which led to the formation of the current government. The room was named in honour of former Army commander-in-chief General Prawit Wongsuwan, who is currently serving as deputy prime minister in charge of security affairs and the defence minister.

Many people, including those in power, see the explosion as politically motivated.

Headless nails were used as shrapnel in the improvised explosive device that was concealed in a vase and placed inside the room. The intent of the perpetrators seems to have been to cause injuries, or even deaths, unlike the two previous explosions in Bangkok earlier this year when no shrapnel was used.

Authorities said they were convinced that the same group of people were responsible for all three explosions – one outside the old Government Lottery Office building on Rajdamnoen Avenue on April 5, one in front of National Theatre on May 15, and the latest at Phramongkutklao Hospital on Monday. They pointed out that similar materials like blue PVC pipes, integrated circuit timers and capacitors were used in all three explosions. Also, there was a common composition of the home-made bombs in the three explosions.

It is still too early to point a finger at any particular group of people as being behind the latest explosion at the hospital.

It is obvious that this latest attack was politically motivated but it remains unclear whether the perpetrators are opposed to those in power or come from among them. In order to find out possible culprits, we need to first determine the motivation and the beneficiaries from the action.

There are five possible motives.

For the government’s enemies, the explosion was an opportunity for them to show their ability to oppose those in power. Some hardline critics of the government hailed the incident as the beginning of serious opposition to the post-coup administration, which has been in power for almost three years.

For the authorities, the explosion at a hospital is a sufficient excuse to crack down on hardcore dissidents, many of whom are accused of violating the law by insulting the monarchy. It is likely that after this incident there will be a major crackdown on such people, who have been mainly active on social media.

For supporters of the National Council for Peace and Order and the government led by Prime Minister Prayut Chan-o-cha, the latest explosion in the capital is good reason for Prayut to stay on in power on the pretext of maintaining peace in the country. Thailand has remained mostly peaceful after the coup but the government’s popularity has been on the decline and is seen to be on the way out as the countdown begins for the next general election.

For some people in the government, certain members of the Cabinet need to be replaced, and yet another explosion in the capital could help hasten that replacement, particularly someone responsible for security affairs.

The last possibility involves insurgents from the restive southern border region. They may be the least likely to be the perpetrators of the hospital attack, but some security sources say insurgent bomb experts may have been hired to make explosive devices to be planted at the hospital.

More than a decade ago, southern insurgents were also linked to multiple bombings in Bangkok during the New Year countdown party at a downtown shopping mall in 2006. That was just a few months after the military coup in September that year, which overthrew the government led by Thaksin Shinawatra.

In 2007 and 2010, there were four more roadside bombings in the capital, one outside the Criminal Court. Bomb disposal experts said the devices used then were similar to the one used at Phramongkutklao Hospital.

Although some suspects were arrested, no culprits have been prosecuted for the politically-motivated explosions in the past. Hopefully, the culprits will be brought to justice on this occasion.