Dakota Theriot, the onetime fugitive who stands accused of murdering his girlfriend, her relatives, and his own parents, pleaded not guilty to three of those murders in court Monday, The Washington Post reports. In Louisiana, the 21-year-old denied allegations that he murdered Summer Ernest, his girlfriend, and her father, Billy, and brother, Tanner, this January. But prosecutors allege that after a fight between the couple, Theriot shot and killed the Ernsts before driving to another parish to murder his parents. He was eventually arrested in Virginia, where police allegedly found him driving by his grandmother’s home with a firearm poking out of a car window. Livingston Parish District Attorney Scott Perrilloux told the Post that he had looked into the possibility that Theriot was mentally ill, but decided that there was no reason not to seek the death penalty.