CNN — A man serving life sentences for three 2005 Las Vegas-area murders has now been charged in a 2004 killing there, authorities said Thursday. Investigators determined Norman Flowers, 48, is a suspect in the 2004 death of Keysha Brown after they asked for more forensic testing during a July 2022 cold-case review of the killing, Las Vegas police said Thursday. The police department’s forensic laboratory in December gave detectives a report “confirming … Flowers was the suspect” in Brown’s death, police said in a news release . Details about what the forensic testing entailed or why any such testing didn’t help identify a suspect years ago weren’t immediately available. CNN has sought comment from Las Vegas police. Flowers has been charged with open murder and sexual assault in the 2004 case, according to court records and police. Flowers is serving three life sentences at Nevada’s High Desert State Prison on convictions of first-degree murder in the 2005 killings of three women in th e Las Vegas area: Sheila Quarles, Marilee Coote and Rena Gonzalez, authorities said. Brown was found dead a few blocks east of the area’s famous strip of casino hotels and miles south of downtown Las Vegas on October 19, 2004, police said. Brown had been stabbed, beaten, strangled and sexually assaulted, police said. At the time, detectives couldn’t identify a suspect, police said. Police have not said whether they know of a motive in Brown’s death. As for Flowers’ open murder charge : In Nevada, that charge is a general homicide allegation that would allow a jury to decide the level of the offense at conviction, including first-degree murder, second-degree murder, voluntary manslaughter or involuntary manslaughter.