Convicted killer adds 3 slayings to his list

BOISE — One veteran law enforcement officer says Joseph Edward Duncan III's murderous hammer attack on a north Idaho family is the worst example of evil he's ever seen.

Now federal prosecutors say Duncan's evil extends to two slayings in Washington state in 1996 and another in California in 1997.

The 43-year-old convicted killer and child molester has confessed to the three additional slayings, Assistant U.S. Attorney Wendy Olson said Tuesday in a court filing by which the government declared its intent to seek the death penalty against Duncan in a separate federal case here.

In the current Idaho federal case, Duncan is accused of kidnapping the two youngest children from the slain Idaho family and later killing one of them. Prosecutors say Dylan Groene, 9, was killed at a remote Montana campsite while his then 8-year-old sister Shasta Groene watched.

The children's mother, Brenda Groene; her fiance, Mark McKenzie; and the younger children's 13-year-old brother, Slade Groene, were bludgeoned to death with a hammer during the May 16, 2005, attack, crimes for which Duncan is already serving life in prison.

"It's by far the worst case that I've ever experienced," Kootenai County Sheriff Rocky Watson told The Associated Press recently.

Duncan has spent most of his time behind bars following his 1980 conviction for raping a 14-year-old boy in Tacoma, Wash., at the point of a stolen gun. Each time he got out — for several years in the mid-1990s on parole that he eventually violated, and finally in 2000 at the end of his 20-year sentence — prosecutors say his crimes resumed. The U.S. Attorney's Office here said Duncan acknowledges killing Carmen Cubias, 9, and Sammiejo White, 11, in Washington state and Anthony Martinez, 10, in California.

"The defendant has engaged in a continuing pattern of violence, attempted violence and threatened violence," Olson wrote, justifying her office's bid to have Duncan put to death. He "is likely to commit criminal acts of violence in the future that would constitute a continuing and serious threat to the lives and safety of others."

Roger Peven, Duncan's attorney, hadn't yet seen the filing and could not immediately comment on it. Peven had met with Duncan early Tuesday but declined to comment on the meeting. Duncan is being held in a state prison near Boise.