A 22-year-old Idaho man has pleaded guilty to first-degree murder in the killing of a former Arizona power company executive, his wife and their adult son at their Boise home.

Adam Dees of Nampa appeared Friday in 4th District Court to enter his plea to three counts of first-degree murder and one count of robbery. In exchange, prosecutors say they will not seek the death penalty.

Prosecutors allege Dees killed 80-year-old Theodore M. Welp, 77-year-old Delores Elaine Welp, and 52-year-old Thomas P. Welp on March 8 or 9. The bodies were found March 10.

An indictment says all three were shot in the head and beaten with a baseball bat. Authorities say Dees was found with credit cards linked to the family and tried to sell Elaine Welp's engagement ring.