A US fashion designer has been sentenced to 59 years to life in prison for sexually assaulting aspiring models he lured to Los Angeles.

Superior Court Judge David Wesley sentenced 35-year-old Anand Jon Alexander, who was convicted in November 2008 of 14 counts including forcible rape.

He was found not guilty of four felonies and jurors could not reach a verdict on three counts.

His victims, some of whom spoke at the hearing, ranged in age from 14 to 21.

Prosecutors said Alexander often found women online, baited them with promises of glamorous photo shoots and other modelling work, only to fondle or rape them at his Beverly Hills apartment.

His sentencing caps a tumultuous post-verdict saga that included allegations of juror tampering by his sister, Sanjana, juror misconduct and Alexander's decision to represent himself.

In July, Superior Court Judge David Wesley found juror Alvin Dymally and Sanjana Alexander in contempt of court after determining Dymally appeared to want a romantic relationship with her when he spoke to her by phone twice during the trial and offered his help.

Dymally also gave her a note in a courthouse cafeteria, asking her to call him. She did but refused to meet him alone.

The judge held her in contempt for contacting the juror and failing to report the misconduct. A hearing will be held in September.

Wesley, however, did not grant Alexander's motion for a new trial, saying there wasn't any proof the phone conversations swayed the verdict.

The designer has been featured on the television show America's Next Top Model and worked with celebrities including Paris Hilton and Mary J. Blige.

His website lists dozens of celebrity A-list celebrities as clients, including Hilton, who is described as a fan of Alexander's hand-printed jeans, which sold for more than $US700.

Beverly Hills police began investigating Alexander in March 2007 when a woman reported she had been sexually assaulted in his apartment.

During the trial, prosecutors relied heavily on the testimony from women who made the accusations against Alexander.

Defence lawyers argued many of women were lying about what happened to them and sought revenge against Alexander when they didn't get modelling jobs.

He is under indictment in New York on similar charges involving nine women.

Born in India, Alexander graduated from the Parsons School of Design in New York and launched a fashion line in 1999.