The late actress's father wanted the coroner to turn over Murphy's hair samples that he believed would prove she didn't die from pneumonia and anemia.
The lawsuit was tossed when Murphy's father failed to show up in court for a second time.
Murphy was found dead inside her Hollywood Hills home in 2009 by her husband, Simon Monjack.
Monjack died the following year, also as a result of pneumonia and anemia, according to the coroner.
