Milke, 49, was released from prison, on bond, in September. She was convicted in 1990 of arranging for two men to kill her son, 4. Her conviction was overturned by an appeals court in March, the court citing the prosecution's failure to turn over evidence that called the state's key witness, a detective who told jurors Milke confessed, into question.
Milke's attorneys claimed a retrial should not be permitted because of prosecutors' misconduct, and that it amounts to double jeopardy. Prosecutors argued that mistakes may have been made but there was no attempt to intentionally deceive Milke's lawyers, KPHO-TV, said.
In a four-page ruling, Mroz said "the court cannot conclude that the prosecutor intentionally engaged in conduct he knew to be improper."