10:18 AM PT -- Sources close to Jake tell TMZ ... he meant absolutely no harm or malice with his beach cruising escapade, and is basically pleading ignorance here.
We're told Jake and co. did not see any sign whatsoever out there that indicated there were turtles about, or that they were in middle of nesting. Had he seen that, our sources say Jake never would've gone out there ... but just didn't know.
On top of that, we're told Jake saw other people driving around the sandy shores as well that day -- so he figured it was kosher, not realizing there was a bigger issue at hand. Our sources say Jake is a huge animal lover and would never intentionally do anything to harm any species out there.
With all that said, we're told Jake is more than willing to cooperate with the Puerto Rican authorities to help protect and preserve important beachfront in the area.
Jake Paul is under investigation ... this time by officials in Puerto Rico for riding a motorized vehicle on a protected beach.
To use a bullfighting metaphor ... Jake waived the proverbial red flag in front of a bull by posting a video of him and some friends tooling around a beach in golf carts, smack in the middle of turtle-nesting season. That's illegal.
It looks like the driver is his brother, Logan, although we haven't been able to confirm.
Jake deleted the vid, but it's too late because the investigation has been launched by the territory's Dept. of Natural and Environmental Resources.
Logan said back in February he was moving some of his businesses, including Maverick Clothing, to Dorado, Puerto Rico ... which is near San Juan. Logan said on his podcast back then, “I thought it was more third-world than I suspected, so I went out there to scout it and I just fell in love with it.” Jake and Logan snagged a $10 million beachfront mansion.
They fell in love with Puerto Rico, but it doesn't sound like everyone there feels the same.