Despite just coming off a grueling fight week at UFC 158 and causing himself a lot of grief, it seems that UFC welterweight Nick Diaz simply can't stay out of trouble.
At least, that's what appears to be happening.
Late on Sunday night, Diaz tweeted a picture of himself sitting on the sidewalk with police cruisers in the background.
Diaz (or whoever has access to his Twitter account) has since deleted the original tweet, but it has since made the rounds on the Internet. Here is the Twitter message as it originally looked prior to deletion:
Fuck they got us:( pic.twitter.com/HdUH0DD1Wk
At the moment, the original picture is still in Twitter's server archive.
According to the timestamp in the image, Diaz originally posted the photo to his Twitter account at 10:58 p.m. PT on March 17, 2013.

Exactly what this means isn't certain, but Diaz most recently turned heads at the UFC 158 post-fight press conference by stating that he had "never" paid taxes in his life:
I've never paid taxes in my life and I'll probably go to jail. No one wants to hear about that, no one wants to hear about that kind of talk or what's really going on with me. I might as well just be a kid.
If true, that would indicate that Diaz has possibly been guilty of years of tax avoidance or tax evasion as early as 2001—the year that Diaz turned 21 years old and started his professional fighting career. What's unclear is whether or not Diaz owes excess federal and state taxes, or if he has simply not filed any taxes during the past eight years.
Diaz's Twitter has not since been updated, so it's currently unknown if he has indeed been arrested or not, or if the photo itself was a prank. If Diaz has actually been detained by police, it's additionally not certain whether or not this incident is related in any way to his self-professed tax troubles.
This event takes place just a day after UFC 158, where Diaz competed in the main event against welterweight champion Georges St-Pierre.
Diaz lost a one-sided unanimous decision to St-Pierre, marking his second-straight loss after an earlier defeat in February 2012 to former interim champion Carlos Condit. Both matches were notably separated by a one-year suspension of Diaz's fight license due to a failed drug test (via MMA Junkie) for marijuana metabolites.

Update: Nick Diaz has posted two additional pictures on his Instagram account, with more shots of what appears to be the police cruiser in the original image.
Diaz's pictures include the following text:
Yes i am on the sidewalk :/
We lost Alix and Vic
Apparently, the situation is continuing to develop, although Diaz has not yet stated his immediate location or the reason that he has currently been detained by the police.