The U.S. Coast Guard released a video showing a daring operation to intercept a minisubmarine stocked full of cocaine.

The raid itself occurred on March 3. Long-range surveillance aircraft based in Texas detected a minisubmarine in the ‘Eastern Pacific Ocean’ headed to American shores. It alerted the U.S. Coast Guard, which sent a crew from Almeda, California to the scene. It confronted the submarine about 300 miles west of Panama.

In the video, the traffickers tried to escape as they saw the Coast Guard closing in. They were quickly arrested, but service members hit a snag–the submarine itself was unstable. Before they had a chance to confiscate all of the drugs, the entire vessel sank beneath the waves.

Only 12,800 pounds of drugs were safely seized by the Coast Guard. The value of that cargo? $203 million.

“In this case we were able to safely remove approximately 12,800 pounds of cocaine from the vessel,” said Cutter Bertholf Commanding Officer Captain Laura Collins. “There was no practical way to tow the vessel several hundred miles back to shore and we couldn’t leave it because it posed a hazard to navigation to other mariners in the area. We sank the smuggling vessel by downflooding.”

 

This the second big Coast Guard-led drug bust of 2016, and its the fifth since June 2015. Smugglers are now using miniature, self-propelled submarines made of fiber glass to deflect radio waves and escape detection by U.S. Customs and Border Protection. Usually manned by a small crew of four, these submarines stay about 30 feet below sea level. Some can coast for as long as 2000 miles before needing to refuel.

No one is really sure where the submarine itself came from or where it is headed.