Those charges stem from the killings of 42-year-old David Lueras, 34-year-old Lauren Phillips and 33-year-old Maricruz Mathis, all of whom he identified as "sacrifices" he felt he was "being called to commit."
At the time of his arrest, he was under investigation for possible ties to the death of his former roommate, 61-year-old Mark Jewell. Until that time, investigators had not found enough probable cause to arrest Thornburg.
On Friday, February 18, however, the office of the Tarrant County District Attorney announced that a grand jury had indicted Thornburg on charges of murder and arson.
According to the announcement, both charges are felonies and punishable by five to 99 years or life in prison.
According to Law and Crime, Thornburg was ordered to undergo a mental health evaluation in October, 2021 by a Tarrant County magistrate who indicated there was "reasonable cause to believe [Thornburg] has a mental illness or is a person with an intellectual disability."
His next court date is not known.