A US serial killer dubbed the "Grim Sleeper" and convicted of murdering nine women and a teenage girl has been sentenced to death.

Lonnie Franklin Jnr's killings took place over more than two decades.

The former bin man became known as the Grim Sleeper because of an apparent 14-year gap between two spates of murders, although police have since claimed to have connected him to other unsolved killings.

The 63-year-old targeted women, some of who were prostitutes or cocaine addicts.

On Wednesday, a judge upheld the jury's decision to sentence Franklin to death.

During his trial which ended in May, a jury found Franklin guilty of killing seven women between 1985 and 1988, and the 15-year-old girl and two women between 2002 and 2007.

The jury also convicted Franklin of attempted murder for an attack on an 11th victim, Enierta Washington, who survived being shot in the chest, raped, pushed out of a car and left for dead in 1988.

A Polaroid photo of her partly nude and bleeding from her wound was found in Franklin's garage after his arrest.

Ms Washington testified against him at the trial, and pointing at him in court said: "That's the person who shot me."

Deputy District Attorney Beth Silverman said Franklin's motive was "doing evil", and his "degrading, calculated and brutal" crimes had destroyed many lives.

Franklin, who was also a former garage attendant for Los Angeles police denied any role in the killings, but did not utter a word in his defence during his trial.

Franklin's lawyers had suggested a mystery man was the real killer and has asked jurors to spare the defendant's life.

He showed no emotion as the verdicts were read.