Phoenix ? The state Supreme Court on Friday overturned a man’s murder convictions and death sentences in a Tucson triple slaying after finding that a prosecutor misled jurors.

By using false testimony to bolster a key witness’ credibility, Kenneth Peasley, a two-time state prosecutor of the year, deprived Andre Lamont Minnitt of a fair trial, the Supreme Court said Friday.

Peasley’s conduct amounted to “calculated deception” intended to cover up weaknesses in his case, Chief Justice Charles E. Jones wrote in the 5-0 ruling.

Minnitt cannot be tried again on murder and other charges stemming from a June 24, 1992, robbery of the El Grande Market in Tucson. He still must serve a 36-year sentence for another armed robbery.

Minnitt’s first two murder trials, both handled by Peasley, ended in an overturned conviction and a mistrial, respectively. The high court said it threw out the convictions from Minnitt’s third trial, which Peasley did not prosecute, because the damage from the first two trials had already been done.

“Whether or not the third trial was free from false testimony, falsehoods in the two previous trials permeated the process to the extent that fairness in the third trial could not correct the misdeeds of trials one and two,” Jones wrote.

Peasley, a veteran homicide prosecutor, stepped down as Pima County’s chief criminal deputy in June 1999 when the state bar association found probable cause to investigate him. He remains a deputy county attorney but no longer handles criminal cases.

The court found that Peasley elicited false testimony from former Tucson police detective Joe Godoy.