Ray J -- Police Shooting ... LAPD Investigates

Ray J had a bizarre encounter with cops Wednesday ... one minute being ordered out of his car and the next taking pics with them ... and the pics have triggered an LAPD investigation.

Ray was tooling around in his new Bentley in the San Fernando Valley when the 2 officers noticed he was holding his cell phone ... appearing to text.

Ray J tells TMZ ... the 2 cops pulled him over and told him it was illegal to text and drive. They were also suspicious about the car because it had no license plate but a customized "RJ" frame.

Ray tells us ... he explained he was not texting but simply struggling to connect his blue tooth. The cops then ran his license and registration, came back to the car and warned him if he was texting he shouldn't do it anymore. They also asked if he was in the music business.

It seems like that should be the end of the story ... but it was just beginning. Ray tells us the 2 cops ordered him out of the car and he was panicked things would go downhill. He got out, and Ray says the cops then asked if they could take a few pics with him.

The cops took cell phone photos and then Ray asked if they would return the favor and take a few pics on his cell phone -- they obliged, and we have the pics.

Our law enforcement sources tell us ... the LAPD has now launched an internal affairs investigation. An LAPD big wig tells TMZ ... it's against policy for cops to take a pic with a driver after letting him off the hook because it creates an appearance of impropriety.