Was that Mark Cuban’s yacht in Boston Harbor?

Boston Police

Dallas Mavericks owner and television personality Mark Cuban insists — really insists — that a massive, 288-foot-long yacht, complete with a basketball hoop, that had been docked in Boston waters is in no way, shape, or form his vessel.

Boston police Monday begged to differ. They shared on social media an image of kids leaning out from the side of a boat on the harbor, staring up at a glistening yacht they believed belonged to Cuban.

“The kids got a kick out of seeing [Dallas Mavericks’] Mark Cuban’s yacht in Boston Harbor!,” police said on Twitter.

The children were on the police boat, marveling at the large vessel and its many shiny components, as part of the police department’s summertime Jr. Police Academy program. It was unclear when the image was taken. Police did not immediately return a request for comment.

It seems the yacht has since left the Boston area. It was logged Monday as being docked in Portland, Maine, according to MarineTraffic.com.

But were they actually looking at Cuban’s boat?

The “Is-that-Mark-Cuban’s-yacht?” rumors have been swirling locally since the massive luxury ship first arrived in the city’s North End neighborhood, at Boston Yacht Haven, earlier this month.

They go back even further, however. Since last summer, when the boat was spotted in Maine, reports have pegged Cuban as the boat’s owner.

But Cuban told the Boston Business Journal in a message sent through the billionaire entrepreneur’s own app, Cyber Dust, that it’s not his.

“I don’t have a yacht,” he reportedly said to technology reporter Sara Castellanos, before the message vanished.

And he shouted it (no, really, he wrote it in all capital letters) in a statement to the New York Post’s Page Six, after being pestered about the mystery of the boat’s ownership yet again.

“The guy who owns the boat tells everyone that it’s mine,” Cuban told the gossip page in early July, after the yacht, called “Fountainhead,” an apparent tip-of-the-hat to the Ayn Rand book of the same name, appeared in the Hamptons.

“It’s so crazy . . . I don’t even own a boat,” he added, making sure the weight of the statement hit harder than an anchor to the ocean floor.

It’s been reported that the yacht is actually the property of Sears chief executive Eddie Lampert. The conversation about who is at the helm of the yacht seemed to have sunk, for a time, into the depths of the ocean.

But with the latest allegations from Boston police, it looks like the rumors may have bobbed back to the surface.