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Rob Kardashian is being criminally investigated by authorities for allegedly making threats against a man who is friendly with his fiance Blac Chyna.

TMZ is reporting that the "Rob and Chyna" star physically threatened a man named Pilot Jones because he's been hanging out with his baby mama.

The website says Rob sent Pilot a string of text messages in which he warns him to stay away from Chyna.

"Leave my wife alone," he allegedly wrote in one message. "I'm not playing with you."

There are others like that, TMZ said, although one source said the threat is "a little murky and general."

Officers from Los Angeles Police's Threat Management Unit are investigating the claims.

The alleged threats come after photos surfaced of Chyna and Pilot making out. It's not known when the photos were taken. Internet muckrakers have been implying for months that Pilot could be the father of Chyna's unborn child, but those claims seems to be unfounded.

Rob and Chyna are expecting a baby girl in November. Things haven't always gone smoothly for the duo. Last month she tweeted out his phone number to ensure that women were not texting him.

But, there have also been reports that the duo has broken up and that the are only acting united when the cameras are on them.

"If you ask Rob, he'll say they're having issues. If you ask Chyna, she'll say they are not together," a source told Entertainment Tonight in September. "Their relationship is not in a good place right now but they are working on it."

Around the same time, TMZ said they were "seriously on the outs."

"Rob and Chyna haven't been speaking for months," the reputable celebrity website said. "They briefly reunited for a dinner the night before their reality show premiered, but other than that, they've been split."

For what it's worth, the couple has blasted those reports.