A post-mortem examination determined she had been strangled, stabbed in the neck, and had suffered blunt force trauma to the head.
After an extensive investigation, police implicated 29-year-old Christopher Scott Wilson – a beauty school classmate of Cowell's – in her death.
Police began to suspect Wilson after several people came forward claiming that he had a fascination with death and serial killers.
[3] Cowell's purse and some clothes were found in the car, although her debit card and cell phone were missing.
[4] The Chelan County Sheriff's Office began the investigation into Cowell's disappearance by using a helicopter to search the area near where her car was found.
[4] On the afternoon of February 13, Cowell's body was discovered by a passer-by on the banks of the Columbia River near Quincy, Washington, at a resort community about 20 miles (32 km) away from Wenatchee.
[5] On February 25, around 1,800 people attended a memorial service for Cowell, which was held at the Town Toyota Center in Wenatchee.
Reid told police that two drug dealers, Sam Cuevas and Emmanuel Cerros, had murdered Cowell in a case of mistaken identity.
[7] Reid was able to describe the murder weapon before it was made public, and gave police a ring which she claimed had belonged to Cowell.
Cuevas and Cerros were interviewed by police and produced alibis, witness statements and phone records placing them elsewhere on the day of Cowell's disappearance.
[11] After receiving several tips, police began to focus the investigation on Christopher Scott Wilson, a 29-year-old classmate of Cowell's at the Academy of Hair Design.
Police received a letter in August which claimed that Wilson had an "obsession with death, dead bodies and serial killers".
[13] Prosecutors upgraded Wilson's charge from second-degree to first-degree murder in April 2011, stating that his actions constituted premeditation.
[14] Before the trial began, Wilson rejected a plea deal in which he would have received a prison sentence of about six and a half years in exchange for pleading guilty to first-degree manslaughter.
[15] Wilson's defense team was led by John Henry Browne, a prominent Seattle attorney who had previously represented high-profile defendants such as Ted Bundy and Colton Harris Moore.
[7] The presiding judge ruled that the defense would be allowed to present evidence implicating Cuevas and Cerros as the killers.
The judge also ruled that the prosecution would not be allowed to bring up Wilson's work history at area funeral homes, his tattoo of Hannibal Lecter, or his online activity on DeviantArt and on serial killer forums.