Authorities announced Monday that at least 12 employees of the Pakistan International Airlines (PIA) were arrested for allegedly attempting to smuggle 6 kg (13.23 lb) worth of heroin.

The heroin was found in the toilet of a flight during a raid conducted by the military-run Anti-Narcotics Force on Saturday. The heroin was reportedly worth at least 60 million Indian rupees ($900,000). The Anti-Narcotics Force received a tip-off claiming that a huge quantity of the substance was concealed aboard the flight heading to Dubai from Lahore.

“Around a dozen employees of PIA have been detained and are being interrogated in connection with heroin seizure,” PIA spokesman Danyal Gilani told Reuters. “If proven guilty, they will face action with respect to their jobs, in addition to the legal consequences.”

A probe has been launched into the matter, Gilani said. This isn’t the first time such an incident has taken place. PIA employees have, in the recent past, been caught red-handed attempting to smuggle a variety of things including drugs, cigarettes and illegal passports.

Reports said that in June 2015, the national carrier dismissed five employees who had been detained in the United Kingdom for attempting to smuggle foreign currency. In 2013, a PIA pilot was jailed for nine months in the U.K. He was found to have been three times over the U.K’s legal alcohol limit for flying and was to pilot a plane carrying nearly 156 people.