The three textile engineering students clinging on for life at Dhaka Medical College Hospital had died from burn injuries.

Hafizur Rahman Hafiz, 24, died around 1:00am and Dipto Sarkar, 22, around 9:30am yesterday. Shahin Mia died on Wednesday.

Another textile engineering student Towhidul Islam, 23, was killed on the spot after an illegally connected gas pipe at their flat exploded on the night of March 25 in Mymensingh.

Although none of them were from well-off families, they had been among top 10 scorers in the class of 2013 in Khulna University of Engineering and Technology, said their family members and classmates.

The final-year students were interns at Square Fashion in Mymensingh's Bhaluka upazila. They lived in a rented-flat in a newly constructed six-storey building in Bhaluka upazila's Masterpara area.

An explosives expert from Counter Terrorism and Transnational Crime unit of Dhaka Metropolitan Police concluded that a leaky gas pipe was responsible for the explosion.

The deaths dismayed over 50 Kuet students, who had come to the DMCH to attend the injured students.

They collected funds and ran errands to make sure their injured classmates had everything needed for their treatment.

Of the victims, Dipto was the second, Towhidul third, Shahin fourth and Hafiz seventh among 57 students of the batch, one of their classmates Bashir Mirdha told The Daily Star.

“Dipto, Towhidul and Shahin would probably become faculty members in our university,” he said.

Shahin's father died two years ago and his elder brother paid for his education, his uncle Shafiqul said.

“Shahin used to say he would support the family after getting a job,” he said.

Hafiz's father, who is a landless farmer in Naogaon's Manda area, told reporters at the DMCH that he had been struggling to support Hafiz's education and dreaming of better days.

Dipto's brother Narayan from Magura said Dipto used to earn by tutoring younger students. He occasionally sent money to the family.

The family members of the victims and their fellow students demanded the building owner and the people involved in the illegal gas connection be punished.

They also said the victims' families should be compensated for their loss. 

Moshihur Rahman, deputy managing director of Titas Gas Distribution and Transmission Company Ltd in Mymensingh, yesterday admitted that the gas connection to the building was illegal, reports our Mymensingh correspondent.

Asked why no action was taken, he said the company had manpower shortage and could not monitor the illegal connections frequently.

The building owner did not have permission for gas connection and he had installed the gas pipes on his own, the official added.

Monjur Ahmed, who was the company's manager in Bhaluka, got transferred two days after the explosion amid allegations of being negligent to his duty.

“We will take legal action against the house owner after a proper investigation into the incident,” Moshihur said.

No case was lodged by the company so far.

SA Newazi, additional superintendent of police in Mymensingh, said primary investigation revealed that the building was constructed without following the building codes.

A team of Kuet teachers visited the spot yesterday, police said.

Mamun-or-Rashid, officer-in-charge of Bhaluka Police Station, said a case accusing the building owner Abdur Razzaq Dhali of causing death by negligence was filed on Sunday night.

He added that the owner had gone into hiding after the incident.

Two probe bodies were formed by police and district administration on Sunday to investigate the explosion.