Diddy charged with 3 counts of assault with a deadly weapon & one count of making terrorist threats via @iam_bobokanbai

Diddy charged with 3 counts of assault with a deadly weapon & one count of making terrorist threats via @iam_bobokanbai

Our Diddy sources tell us ... Diddy insists the drama began during a workout session yesterday because strength and conditioning coach Sal Alosi was "riding Justin badly" and told him not to come back until the end of the summer. 

Diddy went to the campus today to speak with Alosi -- believing he has an "issue" with Justin -- but things didn't go well when he arrived to campus.

Our Diddy sources say the coach would not see him and staff told him to leave ... but Diddy went to Alosi's office instead where Alosi told him to get out and threatened to call security if he didn't leave.

We're told Diddy said, "Fine, I'll call police" ... and Alosi snapped -- going after Diddy with his hands. 

Our UCLA sources tell us Diddy confronted Strength and Conditioning Coach Sal Alosi while Alosi was on the phone. We're told Diddy was told to "hang on" but he wasn't having it and picked up a kettlebell and swung it, narrowly missing Alosi. One source said if Diddy had connected, it could have killed Alosi.

We're told Diddy insists he grabbed a kettlebell and held it up in a defensive position ... but did not attack with an intent to injure the coach.

Source: TMZ