Bangaluru: At least three workers were killed and 14 injured when a four-storey building under construction collapsed in a bylane off Central Jail Road at Kasavanahalli here on Thursday.

Rescue operations were still under way at the time of going to the press. “With the building owner, site supervisor and engineer absconding, we don’t know how many more workers are trapped,” said a National Disaster Response Force (NDRF) officer.

Around 4 p.m., residents heard a loud noise. When they ran outside, they saw the building had collapsed. “We could hear people crying for help inside,” said an eyewitness. Residents began digging through the debris and were able to rescue four workers before eight fire tenders and the Bellandur police arrived at the spot.

Fire and Emergency Services personnel joined the rescue operations about 4.30 p.m., and were able to save five more trapped men. By midnight, six more were rescued. The NDRF teams and Civil Defence personnel were also part of the rescue operations.

However, civic officials are yet to confirm this and are examining sanction plans. Senior police officials said the original structure was at least seven years old and construction of three additional storeys had begun three months ago to convert it into an apartment complex.

Soon after the accident, the site supervisor and one of owners of the building Abdul Rahman were found missing.

“The basement of the building was old and this could be the reason for the collapse, a senior official of the fire department said.

The Bellandur police have taken up a case against the owners under Section 304A of the IPC for causing death due to negligence.

Soon after the accident, the site supervisor and one of owners of the building Abdul Rahman were found missing.

The police have detained members of Rahman’s family, one of the building owners, Sameera, as well the BBMP engineer (Mahadevpura zone) Munni Reddy for questioning.

The work on the building was nearing completion and the labourers are working on the interiors. Most of them hailed from Jharkhand, Raichur, and Kalburgi.

The deceased have been identified as Sher Mohammed, Anwar Ansari and Raju. Among the injured Devendrappa, Bikas, Anil, Mohakam, Amith Kumar, Imam, Raghubis, Ramnivas, and Ramesh have been admitted to hospital.

While the police claim that the construction was unauthorised, Mayor R. Sampath Raj said this would be ascertained only on Friday after he scrutinises the pertinent file.

“There was a seven-year old single-storey building on the 60×40 ft plot, over and above which the builder has built more floors. The pillars have given way. It may be owing to weak foundation and over-building,” Mr. Sampath Raj said.

While the building did get its plan sanctioned, it is yet to be verified whether there were any violations.

“An inquiry has been ordered and the officials responsible will be held accountable,” he said.