SEATTLE — A new study at Seattle University has found Washington death penalty cases cost a million dollars more than similar cases where capital punishment is not sought.

Criminal-justice professor Peter Collins says researchers were not surprised by the results of their seven-month study of the costs associated with the death penalty.

He told The Seattle Times there is a lot of anecdotal and other evidence that already shows the state is spending money on death penalty cases.

The study of 147 aggravated first-degree murder cases filed in Washington state since 1997 quantifies just how much extra death penalty cases cost.

The researchers found the average cost of a death-penalty prosecution and conviction is just over $3 million. Not seeking a death-penalty prosecution and sending a person to prison for life costs the state roughly $2 million.