56-year-old Philip Hanson was arrested back in November. According to court documents, authorities believe he is responsible for sending 30 letters, 16 containing a white powder substance.
Investigators say Hanson targeted individuals, businesses and even a school, including Dayspring Card Company, Arvest Bank in Siloam Springs, Bank of Siloam Springs and Northside Elementary School.
Hanson worked at Dayspring for more than 28 years, and was fired back in November of 2009. Employees at Dayspring identified Hanson as a person of interest, saying he kept to himself, and that he would be capable of sending these letters.
According to court documents, officials began staking out his home and keeping a close watch.
Officials went through Hanson's trash, finding containers with white powder residue, envelopes, and greeting cards, all matching those in the scares, giving authorities enough evidence to make the arrest.
Investigators also say the powder in some of the threatening letters was identified as baking soda, which was also found in Hanson's house.
Hanson went through a psychiatric evaluation after his defender said he might have a mental illness and could have been insane at the time of the crimes. There was question as to whether Hanson had been previously diagnosed with a mental illness and may not have been taking prescribed medication, and that he may have suffered from a severe blow to the head years ago.
According to court documents, Hanson spent time at the Federal Correctional Institution in Fort Worth, Texas. His doctor, and Hanson himself, said he does not have any mental issues and is competent to stand trial.
Hanson officially faces six charges, two for mailing threatening communications and four others for false information and hoaxes. His trial will begin March 6.
The investigation was conducted by the Federal Bureau of Investigation, United States Postal Inspectors, the Benton County Sheriff's Office and the Siloam Springs Police Department.