Four construction workers died and eight were injured after the boundary wall of a residential society collapsed in Noida on Tuesday, PTI reported. Twelve workers were pulled out of the rubble from Jal Vayu Vihar, a housing complex, in the city’s Sector 21 area.

“Four of them died while others suffered injuries in the episode,” Additional Deputy Commissioner of Police (Noida) Ashutosh Dwivedi told the news agency.

Multiple bulldozers were deployed to clear the debris of the collapsed stretch of the wall, which was located adjacent to a drain. Police and fire department officials were pressed into action for rescue operations.

Noida Authority Chief Executive Officer Ritu Maheshwari said that repair work was underway on the drain when the accident occurred.

“The Jal Vayu Vihar society is an old-construction society,” she told PTI. “The boundary wall was also constructed by the society itself and looked weak. The work on the drain outside the society was being carried out on its request by a Noida Authority contractor through a tender.”

Later, the Gautam Buddha Nagar Police said they have arrested a sub-contractor named Gul Mohammad from Sector 20, ANI reported. Mohammad had hired the labourers for the contractor.

The police identified the dead labourers as Pushpendra Singh (25), Panna Lal (25) and Amit (18), all from Budaun district in Uttar Pradesh. The fourth victim was Dharam Veer from Sambhal district.

Uttar Pradesh Chief Minister Adityanath expressed grief at the deaths and directed officials to swiftly carry out rescue operations.