Amanda Bynes has lashed out at Rihanna, saying Chris Brown beat her because she is ''not pretty enough''.

The 27-year-old actress - who was charged with attempted evidence tampering, reckless endangerment and marijuana possession in court on Friday (24.05.13), and since has accused her arresting officer of sexually harassing her - launched a bitter attack on the 25-year-old 'Stay' singer, who was violently attacked by the 'Fine China' singer in 2009, and claims she almost named her dog Rihanna.

The 'Easy A' star wrote on Sunday (26.05.13): ''Chris Brown beat you because you're not pretty enough,'' before adding: ''@Rihanna no one wants to be your lover so you call everyone and their mother that I almost named my new dog Rihanna.''

Rihanna, who recently ended her relationship with Chris and is said to be heartbroken that he appears to have rekindled his romance with his ex-girlfriend Karrueche Tran, hit back at Amanda, writing: ''Ya see what happens when they cancel Intervention?,'' which only enraged the 'She's The Man' star further.

In tweets that have since been deleted, the actress responded: ''@Rihanna unlike ur fugly faced self I don't do drugs! U need the intervention dog! I met ur ugly face in person! U aren't pretty u know it. (sic)''

The New York Police Department's Internal Affairs Bureau is looking into the serious allegations made by actress is a lengthy Twitter rant on Saturday (25.05.16), during which she accused an officer of entering her apartment illegally, slapping her vagina and lying about her throwing a bong out the window in front of him.

Amanda's parents Lynn and Rick are reportedly worried she is bipolar or schizophrenic but cannot force her to undergo a mental evaluation.