Former Bahamian Sen. Pleasant Bridgewater and ambulance driver Tarino Lightbourne, the defendants in the trial, pleaded innocent to charges they told the U.S. movie star's representatives they would leak a sensitive document to the media if he did not pay them $25 million.
The document pertained to the transportation of the Travolta's autistic 16-year-old son, Jett, who ultimately died after suffering a seizure at the family's vacation home.
The jury hearing the case began deliberations Wednesday after closing arguments in the month-long trial wrapped up in the morning.
E! News quoted Senior Justice Anita Allen as saying she declared a mistrial because she suspected juror misconduct.
"The dilemma that we face is great," Allen reportedly told the court without offering details. "I am erring on the side of caution. Justice must be transparent."
Travolta's lawyer, Michael Ossi, said the actor will continue to fully cooperate and will testify again if necessary, E! News said.
Copyright 2009 by United Press International.