Authorities determined that Patino had purchased a typewriter the day before the letters were postmarked. The machine was seized when a search warrant was executed on Patino's home.
Corcione described Patino's initial interview with investigators as "deceptive" and said that they had very little contact with him again "until we put handcuffs on him last night."
Patino did not confess to the murder, Corcione said, but admitted to being in Touma's motel room that night of June 13.
Touma is the third servicewoman stationed at North Carolina military bases killed in recent months. In all three cases, the murder suspects are male GIs in some type of intimate relationship with the victims. In two of the cases, the victims were pregnant.
Authorities found Army 2nd Lt. Holley Wimunc, 24, dead in a wooded area near Camp Lejeune after a suspicious fire at her Fayetteville apartment. Her husband, Marine Cpl. John Wimunc, who allegedly had the help of an accomplice, has been arrested and charged in her death.
Wimunc, a nurse at the Womack Army Hospital whose family is now referring to her by her maiden name, Holley James, was memorialized in Dubuque, Iowa, this week. The couple was reportedly in the middle of a bitter divorce when the soldier was killed.
In January, the burned body of eight-month-pregnant Lance Cpl. Maria Lauterbach, 20, was found in a shallow grave in a back yard fire pit at the home of a former co-worker she had accused of rape.
Cpl. Cesar Laurean managed to flee to Mexico, leaving behind a note in which he denied killing Lauterbach but admitted to burying her remains. He was arrested on April 10 and is awaiting extradition.