A youth who was charged with strangling his mother, placing her body in a car allegedly containing his half-brother and shoving it off a Malibu cliff, was convicted of voluntary manslaughter. Torran Lee Meier, 17, of Canoga Park, had been charged with first-degree murder, but a Van Nuys Superior Court jury acquitted him of that count last week. Judge George Xanthos ordered the jury to continue its deliberations on charges involving the alleged attempt on his 8-year-old half-brother’s life and on two conspiracy counts. Prosecutors said Meier and two friends strangled his mother, Shirley Rizk, 34, in her Canoga Park home Oct. 13, then placed her body in a car with Meier’s half-brother, Rory Rizk, set it on fire and shoved it off a 60-foot cliff in the Santa Monica Mountains. Meier’s two friends, Adam Jay, 18, of Woodland Hills, and Richard A. Parker, 23, of Antelope Valley, are scheduled for trial Aug. 1.