Murphy (previously 8 Mile, Clueless and Just Married) died aged 32 in December 2009.
She collapsed in the bathroom of her Hollywood home on 20 December and was taken to Cedars-Sinai Medical Centre, where she was later pronounced dead.
On Friday (4 March), Spears took to Instagram to say that she is “curious” about the circumstances surrounding the actor’s death, which were the subject of the recent HBO Max documentary What Happened, Brittany Murphy?
In a since-deleted post, as per People magazine, the pop star shared a screenshot of the publication’s recent cover story examining Murphy’s death 12 years later.
“I saw this online today… is anybody else curious??? She died at 32… HMMMMMMMMMMM,” wrote the “Toxic” singer in the caption.
“JUST SAYING !!!! Psss I know it was a while ago but come on …they are STILL INVESTIGATING !!!!”
In February 2010, a report from the coroner’s office declared Murphy’s cause of death as “community acquired pneumonia”, with contributing factors of iron deficiency anaemia and multiple drug intoxication.
Craig Harvey, a spokesperson for the office, told The Associated Press that the drugs involved were all prescription medication but did not specify which they were.
After her husband Simon Monjack, 40, died five months later of similar causes, there was speculation that the couple’s death could have been related to mould growing in their home.
The theory, however, was later dismissed by the medical examiner’s office in 2010.
The Independent has contacted a representative of Spears’ for comment.
The circumstances surrounding Murphy’s death were explored in last year’s HBO Max documentary What Happened, Brittany Murphy?