The accused mailbox bomber will not stand trial. Luke Helder’s admitted to authorities since he was arrested near Reno nearly two years ago that he’s the one who put homemade pipe bombs into rural mailboxes in Illinois, Iowa, Nebraska, Colorado and Texas, injuring two Iowa women and four mail carriers. He also told officers he’d been trying to plant the explosives in a pattern that would make a smiley face when seen on a map. After he was brought to Cedar Rapids, Iowa for a hearing Thursday, the federal judge declared him incompetent to stand trial. Helder’s been at a federal medical center in Rochester, Minnesota, most of the time since he was arrested, and doctors have asked more than once for his court appearance to be delayed while they ran more tests. If they decide in the future that Helder’s competent, he could still stand trial for destroying property and using explosives in a crime of violence, and the charges would carry a life sentence.