The jury expected to hear character testimony from Arias' friends, in a bid for leniency in sentencing after she was convicted of murdering former boyfriend Travis Alexander, but lead defense attorney Kirk Nurmi asked Judge Sherry Stephens for a mistrial and permission to withdraw from the case on the grounds a witness had been intimidated, ABC News reported.
Stephens denied the request.
Nurmi told the court the defense could not continue because one of their witnesses, Arias' childhood friend Patricia Womack, withdrew from testifying, claiming she has received death threats and was conflicted about the case, NBC News said.
Womack was expected to talk about Arias' abusive childhood. Stephens denied the request, NBC said.
Arias, 32, was found guilty of first-degree murder May 8 in the 2008 death of Alexander, 30. Last week jurors determined the murder was committed in an "especially cruel manner," making her eligible for the death penalty.
Court adjourned Monday after lawyers for Arias said they had no witnesses to call.