Los Angeles, California - Aaron Carter's cause of death has yet to be revealed, but his fiancée and mother believe they know what really happened to him.

Carter's fiancée, Melanie Martin, and his mother, Jane, recently told TMZ that they believed Aaron died from a drug overdose.

Aaron passed away on November 5 at the age of 34 after he was found dead in the bathtub of his home in Lancaster by a housekeeper who originally believed he had drowned.

Melanie and Jane say that they were told by the LA County Coroner's Office that no water was found in his lungs, ruling out drowning as a cause of death.

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The two are still awaiting the results of a toxicology report, but they are pushing law enforcement to investigate a drug deal that they say went down the night of his death.

His fiancée claims that a text exchange on Aaron's phone with an unidentified drug dealer suggests the singer owed $800 for an unknown substance. The singer apparently responded that he no longer needs the drug, but the dealer continued to press him for the money.

The text exchange ended with Aaron asking if he was being threatened, according to the late star's family. Melanie and Jane now believe Aaron met with the dealer, possibly purchasing the substance that they believe killed him.

Aaron Carter's fiancée has turned over the phone with the text exchange over to investigators as evidence.