The Delhi Police have discovered a 150-ft-long and 2.5-ft-wide tunnel that had been dug to pilfer oil from an underground pipeline of the Indian Oil Corporation Limited in Southwest Delhi’s Kakrola village. It was found after a low-intensity blast in the area on Tuesday, The Hindu reported.

The blast, which occurred around 9 pm, was caused by excessive pressure resulting from a buildup of natural gas. The police said they had arrested a person named Zubair, who was allegedly involved in stealing the oil, The Times of India reported.

“Zubair told us he had not started stealing fuel and had just finished drilling a hole in the pipeline with the help of a gas cutter,” The Hindu quoted an unidentified police officer as saying. “They covered the opening and placed some bricks and a sofa on it. On Tuesday evening, they removed the sofa and soon after, the blast took place.”

Zubair, a scrap dealer from Daryaganj in Central Delhi, reportedly told the police he was working with a group of four others, who managed to escape. They had dug the tunnel over three months on a piece of land they had rented ostensibly to set up a scrap dumping ground. They got access to the pipeline, which runs from Bijwasan in Delhi to Panipat in Haryana, last week.

“We are trying to find out whether Zubair was planning to sell the fuel,” Deputy Commissioner of Police (Dwarka) Shibesh Singh said. “A case under relevant provisions of law has been registered and the landlord has also been booked for not carrying out a tenant verification.”