By Roland Buerk
BBC News, Gazipur
The only way to get into the ruined lawyers' library at Gazipur courthouse was by stepping over the body of the man the police believe was responsible for the destruction.
Bomb victims' relatives wait anxiously in a Dhaka hospital
He was lying prone on the floor in a pool of blood, naked except for a small piece of cloth.
He was small, with the dark skin and wiry build that marks out a man who works hard in the sun for a living.
It was only when the large crowd that had gathered had had the chance for a good look that the corpse was bundled into a roll of bamboo matting and carried away.
It was roughly done, with much shouting and shoving.
But if it turns out that the police's suspicions are correct then this little man will have his own grisly place in history.
"What we have found here initially suggests it's the act of a suicide bomber," inspector general of police Abdul Qaiyum told the BBC at the scene.
If that proves to be the case, it will be Bangladesh's first suicide attack - a major escalation in what has become a campaign of violence.
Further attacks threatened
The blast at Gazipur was one of two that took place almost simultaneously as people were arriving for work.
Until earlier this year Bangladesh's government had denied there was a problem with Islamic militants
The other happened in Chittagong, the second biggest city in Bangladesh.
There the alleged bomber set off at least one device at a police checkpoint near the courts.
Two officers guarding the building were killed, and the suspect was caught up in the blast.
In all at least seven people were killed in the two attacks, including the alleged bomber in Gazipur.
At least 40 people were injured.
Later a handwritten letter was found near the blast site in Chittagong, police say.
It threatened that similar attacks would continue until the laws of Allah had been established in Bangladesh.
Ninety percent of people in Bangladesh are Muslims. The country's legal system is based on English common law.
The Gazipur blast may be Bangladesh's first suicide bombing
The government has blamed Jamaat-ul-Mujahideen and Jagrata Muslim Janata for a wave of bombings in Bangladesh, and they are the suspects in the latest blasts.
Both Islamic groups were banned in February.
Since then more than 400 people suspected of being members have been detained by the police.
But the men named as the leaders, Abdur Rahman and Siddiqul Islam (widely known as Bangla Bhai, or Brother of the Bengalis), remain at large, despite the offer of large cash rewards.
Courts have often been the target.
In mid-November two judges were killed when a bomb was thrown at their vehicle in the town of Jhalalkati, 120km (75 miles) south of the capital.
In October two people were killed when suspected Islamic militants set off bombs in courthouses in three districts.
And in August bombs went off in towns and cities nationwide almost simultaneously, leaving two people dead.
Until earlier this year Bangladesh's government had denied there was a problem with Islamic militants.
Lawyers and judges have been targeted in the recent attacks
It is a four-party coalition that includes two Islamic parties.
The government has rubbished repeated claims from the opposition, and recently from a dissident ruling party MP, Abu Hena, that elements within the coalition are sheltering violent groups.
Mr Hena was expelled from the Bangladesh Nationalist Party, the largest in the coalition, after making his allegations.
For now, the inspector general of police, Abdul Qaiyum, says the top priority of the police is to find potential suicide bombers.
They are hoping to arrest them before they can strike.
"Everybody should be worried," said Fazle Rabbi, the deputy commissioner of Gazipur in his office in the court complex where the blast took place.
"We do not have the expertise and other things to face that. The most developed countries are also reeling in front of these sort of attacks.
"You know our infrastructure and other things so we can't afford these attacks."