More than a ton of cocaine worth nearly $400 million was seized off the coast of Australia during a drug bust that ended with the arrests of five men on Friday, local authorities said.

New South Wales (NSW) Police Force investigators obtained intelligence about a suspicious purchase of a boat with a large sum of cash in late April and began following the movements of the vessel and people involved, the NSW and Australian Federal Police (AFP) said in a joint news release.

Both the NSW and AFP monitored their activities as they traveled north via Nelson Bay and Port Macquarie, according to the agencies.

When the vessel came back to shore on Friday, marine authorities launched an interception. 

The two men arrested on the boat were charged with supplying a prohibited drug in a large commercial quantity, while the three men arrested on shore were charged with taking part in supplying a prohibited drug in a large commercial quantity. All five face charges of participating in a criminal group.

All five men appeared in court and were denied bail.

Investigators are working to learn more about the origin of the drugs and the group’s alleged associates.