Nicholas Brooks was sentenced to 25 years behind bars in September, 2013 after being found guilty of strangling and drowning his fashion designer girlfriend Sylvie Cachay in the bathtub of their New York City hotel room in 2010.

Brooks launched an appeal against the conviction, insisting the trial judge had not let an expert pathologist testify that Cachay's death was an accident.

However, judges at the state Appellate Division in Manhattan disagreed with his argument and Brooks lost his appeal on Tuesday (22Dec15).

They ruled the "forensic pathologist was not an expert in toxicology and could provide no authority to support his theory" that Cachay accidentally drowned.

His composer father, who wrote 1970s song You Light Up My Life, took his own life in 2011 while fighting charges of sexual abuse.