LOS ANGELES—A Los Angeles business manager whose clients had included Nicki Minaj and the Kardashians was killed, and her boyfriend was charged with murder and torture, authorities said Wednesday. Police found Angela Kukawski, 55, dead in her car in Simi Valley northwest of Los Angeles on Dec. 23, a day after she was reported missing, police said in a statement. Her 49-year-old boyfriend, Jason Barker, was arrested Tuesday and charged with counts of murder and torture, authorities and public records said. Kukawski died from sharp and blunt force injuries to the head and neck and strangulation, the Ventura County coroner said. A criminal complaint from Los Angeles County prosecutors alleges Barker also tortured her with a knife before her death. Detectives believe Barker killed Kukawski inside their home in the Sherman Oaks section of Los Angeles, put her inside her car, drove it to Simi Valley, parked it and left …