DENVER -- Prosecutors have filed murder and attempted-murder charges against a man accused of fatally shooting a 2-year-old boy and wounding the boy's father.

Authorities say 40-year-old Earl Ryan shot and killed Noah Crookham and wounded 30-year-old Thomas Crookham on Sunday.

Prosecutors on Thursday formally filed charges of first-degree murder, fatal child abuse, attempted first-degree murder and first-degree assault.

Ryan had been living in the basement of Thomas Crookham's estranged wife's home, and had been intimate with her at least once, Thomas Crookham told police.

When Thomas arrived at the house, as he and his wife were trying to reconcile, Ryan grabbed a gun and told Angela Crookham, "This is it," Angela Crookham said.

When he saw that Ryan had a gun, Thomas grabbed his son, Noah, when the child was struck in the chest and killed. It was one of several bullets fired at them, police said.

Ryan is an online rare-books dealer and was once valedictorian of Colorado Springs School. In college, he published a conservative magazine for Rice University, and because of his well-thought out opinions, he appeared on ABC's "Nightline" show arguing against Secretary of Defense Robert McNamara. Neighbors described him as a nice man.