Court of Criminal Appeals upholds life sentence for Dan Triplett in Brent Mack murder

The Oklahoma Court of Criminal Appeals has upheld the life without parole sentence for Dan Triplett, the former Guthrie city councilman and businessman convicted of the 2021 murder of Brent Mack.

Triplett, now 70, was found guilty in February 2023 of first-degree murder and desecration of a human corpse after a Logan County jury deliberated for less than two hours. The trial revealed that Triplett and 50-year-old Brent Mack worked together on a septic tank installation site in Mulhall, where Triplett shot him in the back and buried his body beneath the concrete tank.

Following his conviction, Triplett was formally sentenced to life in prison without the possibility of parole. The sentence was appealed to the Oklahoma Court of Criminal Appeals by Triplett.

The appellate court affirmed both Triplett’s conviction and sentence, effectively exhausting his standard appeals and confirming that he will remain imprisoned for the remainder of his life. The decision came last week and was filed in court on May 1.

A three-judge panel consisting of Judges Gary Lumpkin, William Musseman, and Scott Rowland ruled on the appeal in Dan Triplett’s case. Judge Robert L. Hudson recused himself from participating in the decision.

In total, Triplett filed seven appeals to overturn the verdict and sentence. Among his claims, Triplett argued that:

His attorney failed to file for a change of venue to move the trial out of Logan County.
His attorney failed to introduce specific evidence regarding Brent Mack’s criminal history.
The trial judge erred in allowing the State to admit evidence of Triplett’s alleged extramarital affairs, which he claimed were irrelevant and prejudicial.
The State presented insufficient evidence to support the charge of desecration of a human corpse.

Triplett argued that the accumulation of these alleged errors denied him a fair and reliable trial. However, the appellate court rejected these claims, determining that none warranted a reversal or modification of the sentence.

The case gripped Guthrie and the surrounding communities after Mack was first reported missing. Investigators uncovered a trail of data, surveillance footage, and forensic evidence that ultimately led to Triplett’s arrest and conviction.