LOS ANGELES , California ( CNN ) -- The Los Angeles District Attorney 's Office asked police to do more investigative work before a decision is made on whether charges will be filed in the domestic violence case against singer Chris Brown , according to a spokeswoman for the DA . Chris Brown attends a party saluting music producer Clive Davis in Beverly Hills , California , on Saturday . The LAPD 's chief investigator in case , Detective Deshon Andrews , told CNN he hand-carried his findings to the district attorney Tuesday afternoon . Prosecutors looked at the files and then asked Andrews for `` an additional investigation , '' DA spokeswoman Jane Robinson said . Andrews said that to keep photos and documents from leaking to the media , he has kept the case file closely guarded and allowed no copies of the material to be made . Watch the latest about the case » . Police have refused media requests to hear the 911 call that led to their investigation early Sunday , but Andrews said it mostly recorded the sound of `` a screaming woman . '' Brown , 19 , turned himself in Sunday night after police said they were looking for him . He was arrested on suspicion of making criminal threats . Brown was later released on a $ 50,000 bond . He is expected to appear in court on March 5 . Police said Brown and a woman were in a vehicle near Hollywood 's Hancock Park early Sunday when they became involved in an argument . The woman `` suffered visible injuries and identified Brown as her attacker , '' police said . Police did not identify the woman , but sources close to the couple told CNN the alleged victim was his girlfriend , singer Rihanna , 20 . Brown 's lawyer has not responded to several requests for comment . CNN 's Jennifer Wolfe and Ninette Sosa contributed to this report .
NEW : L.A. DA 's office wants more investigation of Chris Brown case . Police : Brown turned himself in after woman accused him of attacking her . Police have n't named woman ; sources say it was girlfriend Rihanna .