AceShowbiz -

Rihanna is said to be very cooperative with the authorities who are conducting investigation against her boyfriend Chris Brown for alleged domestic violence felony battery, stemming from a heated argument which occurred on February 8. The Barbadian singer is providing more evidence concerning the incident, reportedly telling police that Chris choked her, causing her to lose her consciousness. Worse, he even threatened to kill her.

Citing an unnamed source close to the investigation, E! News reports the celebrity lovers got involved in an argument shortly after leaving Clive Davis' pre-Grammy party on late Saturday, February 7. Things went worse after Chris pulled his silver Lamborghini to the side of a street in L.A.'s Hancock Park neighborhood, during when Rihanna grabbed the car's keys and tossed them out the window, leading Chris to get mad.

Unable to find the keys, Chris got back to his car and put his hands around Rihanna's neck, reportedly telling her, "I'm going to kill you!" Rihanna subsequently lost her consciousness, and when she awoke, Chris had left the scene.

The source testifies further that Rihanna's "right eye was blackened and badly swollen and she had hand prints on her arms." Officers who arrived at the scene quickly drove her to the hospital, reportedly to the Cedars-Sinai Medical Center, in their squad car. Officers took two sets of photographs of her bruises, one at the scene and the other after she was admitted to the hospital.

Those photos, according to E! News, would likely be presented to the district attorney as evidence in relation to the case. The evidence could later on be used to file possible charges against Chris, who hasn't issued a single word on that matter.