The on-and-off couple broke up over the Fourth of July weekend, according to RadarOnline. The pair spent July 4 together at a party in Malibu, and appear to have split soon after.
"Karrueche and Chris are done," a source tells the website. "They're not speaking."
The breakup may be related to a racy snapshot Brown posted of Tran Friday on Instagram. The 25-year-old singer put up a picture of his girlfriend's bare backside with only a thong and bra to protect her modesty. While Brown has deleted the photo, Tran has commandeered it for her profile picture on Twitter. The two have reportedly purged pictures of each other from Instagram, and the 26-year-old model has tweeted several cryptic messages.
Brown and Tran first started dating in 2011, but the singer ended the relationship in October 2012 due to his lingering feelings for Rihanna. Brown was convicted of assaulting Rihanna in 2009, but he and the "Diamonds" singer rekindled their relationship for several months before breaking up again in May 2013.