A new documentary has questioned Brittany Murphy's cause of death.

The 'Clueless' actress was just 32 when she died in 2009 and the Los Angeles County coroner ruled her death was an ''accident caused by a combination of pneumonia, an iron deficiency and multiple drug intoxication'' but the new show delves deeper into this.

Investigation Discovery network's 'Brittany Murphy: An ID Mystery' aired in the US this week and dug into Brittany's life and death, including her marriage to Simon Monjack - who died from acute pneumonia and severe anemia just months after Brittany's demise - and the downturn in her career.

The show's narrator said: ''Many connect Brittany's diminished career to a change in her life.''

A press release for the documentary stated: ''Brittany Murphy is a rising star who had it all, beauty, fame, and success ... but she also had secrets. When she is found dead in her Los Angeles home at just 32 years old, Hollywood and legions of fans are left in disbelief. While her autopsy reveals that she died of natural causes, many believe foul play is involved.

''Then, within months, Monjack perishes under strikingly similarly circumstances - in the same bed he and Brittany once shared, only this time, allegedly with Brittany's mother sleeping beside him.''

The TV special also featured a final interview with Angelo Bertolotti, Brittany's father, who died last year at the age of 92.

The press release continued: ''In an exclusive final interview, the late Angelo Bertolotti, Brittany's father, casts doubt on the conclusion that she died of natural causes and reveals bizarre allegations against other family members.''