Duke Wasn't on Police Radar: The 33-year-old man was not known to the police and was not considered a potential suspect. The police interviewed multiple people and had hundreds of leads in the case over nearly 12 years. But Duke was not among them.
Duke graduated from Irwin County High School in 2002, three years before Grinstead went missing. Grinstead was a teacher at Irwin County High School, but it is not known if she had any personal or professional relationship with Duke.
Duke's arrest started with a walk-in tip. It is not known who made the tip, or what their relationship is to Duke or Grinstead.
The missing woman's older sister spoke at the vigil.
Police say Duke burglarized Grinstead's home and "used his hands" to kill her. This was revealed in an arrest warrant on Thursday. Warrants also allege Grinstead was killed in her home and her body was later removed.
Grinstead's home was locked, but her car was unlocked when she went missing. There was $100 in her car and clay on the tires. Her purse and keys were missing from the home.
One of Grinstead's former colleagues remembers Duke as a "polite" former tennis player. Wendy McFarland, an Irwin County High School teacher, recalled Duke as "nice" and "a very bright student." He also reportedly played football.
Police say their investigation is continuing. They expect to interview additional people. They would not say if Grinstead's body has been recovered.