LOS ANGELES (CNN) -- Chris Brown acknowledged last week he had renewed his "friendship" with Rihanna, the woman he was convicted of beating on the eve of the Grammys in February 2009.
Brown, 23, has two more years of probation to serve for his felony assault conviction, although the judge lifted the "stay away" order that kept him from his victim last year.
The singer sent an unsolicited statement to CNN announcing he was breaking up with Karrueche Tran, the 24-year-old model he began dating a year after he was arrested for the felony assault.
"I have decided to be single to focus on my career," Brown said. "I love Karrueche very much but I don't want to see her hurt over my friendship with Rihanna. I'd rather be single allowing us to both be happy in our lives."
Tran tweeted a short message that appeared directed at Brown: "Bye baby."
But what caused Brown to break it off with Tran?
The announcement follows publication of paparazzi photos showing Brown and Rihanna together in public and rumors the two entertainers had reunited romantically.
Many are speculating Brown is getting back together with Rihanna.
The talk of their reunion was fueled last month when Rihanna gave Brown a quick kiss and a hug at the MTV Video Music Awards last month as Brown walked to the stage to accept an award.
Rihanna told Oprah Winfrey in an emotional interview in August that Brown had been her "best friend" and she still loved him.
The judge overseeing Brown's case imposed a "stay away" order when she sentenced him to five years of probation, community service and domestic violence counseling for his felony assault conviction in August 2009.
The order, which was to expire in 2014, required Brown to stay 50 yards away from Rihanna, 10 yards if the two are at the same industry event. The judge lifted the order in February 2011 with Rihanna's consent.
"He just can't bother her," Rihanna's lawyer, Donald Etra, said at the time.
Brown has made several public apologies to Rihanna for the attack, which he seemed to blame on his youth. He was 19 at the time.
"I feel like that we're young," Brown told CNN's Larry King days after his sentencing. "We're both young. So nobody taught us how to love one another. Nobody taught us a book on how to control our emotions or our anger. I'm not trying to fall on the fact that I'm young. I'm just saying it's a lot of stuff that I wish I could have changed that night."
Brown was arrested after an early morning argument inside a rented Lamborghini on a Hollywood street on February 8, 2009.
According to Brown's probation report, the argument began over an incident at a Beverly Hills party. An earlier, sworn statement by Los Angeles Police Detective DeShon Andrews said the incident began when Rihanna found a text message on his cell phone from "a woman who Brown had a previous sexual relationship with."
The pair argued while in the car driven by Brown, the police statement said. It went on to describe the assault in great detail, saying Brown punched Rihanna -- identified in the statement by her real first name, Robyn, and the first initial of her last name, Fenty -- numerous times and put her in a headlock, restricting her breathing and causing her to start to lose consciousness. He threatened to beat her and kill her, according to the statement, and he bit her ear and her fingers.
Eventually, the statement said, "Robyn F. began screaming for help and Brown exited the vehicle and walked away. A resident in the neighborhood heard Robyn F.'s plea for help and called 911, causing a police response. An investigation was conducted and Robyn F. was issued a domestic violence emergency protective order."
The detective said Brown sent a text message nine days later, apologizing.
Rihanna's injuries included cuts and bruises inflicted by a large ring on Brown's right hand, which he used to punch her, the probation report said.
"Officers at the scene observed numerous contusions and abrasions to the victim's face and forehead, as well as bruising to her left arm near the bicep," it said. "They also saw abrasions to her arms near both wrists and on her upper chest near her collarbone and around her neck. There were abrasions on her left leg and on the inside of her upper lips."
Rihanna declined to speak to the probation investigator, so the probation report's details were gathered from police detectives who interviewed her soon after the attack.
"He beat me up," Rihanna told the police, the report said.
Brown made a public apology that July in a video statement posted on his personal Web site.
"I have told Rihanna countless times, and I'm telling you today, that I'm truly, truly sorry in that I wasn't able to handle the situation both differently and better," Brown said in the Web site statement.
"What I did was unacceptable, 100 percent. I can only ask and pray that you forgive me. Please."
CNN's Denise Quan contributed to this report.
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