I don't know much about those boats, but I know they did not have fishing gear on board. Nor were they a luxury yacht. By process of elimination we can assume they are hauling cargo. Most cargo is concerned about fuel efficiency and so would not have that much power for the size of boat (most cargo is on large ships so much bigger engines, but for the size smaller and slower).

I don't know what they were doing, but they didn't match the typical profile of legal things people do. No sign of fishing, no sign of luxury, no sign of water skies...

Due process would still be good, but we know a lot already without that.