The REAL Reason Chris Brown Got Thrown Out Of Rehab & Into JAIL!!

We found out why Chris Brown got booted from his rehab and thrown into jail!

Sources say that he was kicked out for breaking 3 internal rules, which were only his rules. One of those rules was to STAY AWAY FROM THE WOMEN... which Chris allegedly violated.

As for the 2 other violations, we're told Chris left the facility last week on an authorized outing, but when he returned he was told to submit to a random drug test and he refused.  Our sources say he later took the test and the results were negative, but the initial refusal was a violation of rules.

And the third violation ... the facility claims Chris made a mockery of rehab during a group session with some harsh comments.

Our sources say Chris was also in some sort of sexual encounter with a woman at the facility at the beginning of the month, but for some reason that is not part of the basis for booting him.

TMZ broke the story ... Chris was arrested Friday because he violated the order of the judge in the Rihanna case ... the judge required him to stay in rehab for anger management until mid-April, when his Washington D.C. assault case ran its course.

He's currently being held in jail without bail.  His lawyer, Mark Geragos, will appear in court Monday with Brown in an attempt to get him freed.  We're guessing Geragos will ask for house arrest until the D.C. trial.


UPDATE: Chris Brown will stay in jail until April 23 ... he was SHUT DOWN in court Monday afternoon in his bid to win release.