Alissa was last seen at her home in the vicinity of Bell Road and 34th Street in Phoenix, Arizona on May 17, 2001. It was the last day of her junior year at Paradise Valley High School. Her stepfather, Michael Roy Turney, says he took Alissa out of school early and they went out to lunch, then came home. A photo of Michael is posted below this case summary. He stated they got into an argument during the meal because Alissa wanted more privileges, and when they returned home she was upset and went into her room angrily. Michael left her alone at 1:00 p.m. and went to run errands and pick up her sister. He tried to call Alissa while he was gone, but she didn't answer the phone. When he returned to the house at 5:00 p.m., Alissa was gone, leaving behind a note saying she was running away to California. Michael says she called him a week later from a pay phone in California, but quickly hung up. This was the last trace of her.

Authorities initially treated Alissa a runaway and believed she could be either in California or still in the Phoenix area, but foul play is now suspected in her disappearance. She left $1,800 untouched in her bank account and she left her makeup, hairbrush, house keys and cellular phone behind as well. She apparently did take a black packpack with her. Alissa was very close to her siblings, her friends and her steady boyfriend, but she never mentioned any runaway plans to them and none of them heard from her after she went missing. It's uncharacteristic of a runaway to leave behind all her belongings and money, as Alissa apparently did, and to never contact friends or family again. A Florida man confessed to her murder in 2006, but his story turned out to be false. Michael, a former law enforcement officer, says he made over thirty trips to California to look for her.

Alissa's friends describe her as a normal, spirited teenager with a rebellious streak. She had experimented with marijuana and she sometimes skipped class, but she was a good student with a stable home life. Her friends stated Michael was a strict parent who regularly searched Alissa's belongings, monitored her phone conversations and sat outside the restaurant where she worked. He had surveillance cameras set up inside the family home, and telephone conversations in and out of the home were automatically recorded. Michael never gave police the videotape for the day Alissa went missing, but said he had reviewed eight hours of it and seen nothing of interest. He said the phone recording system wasn't operating the day Alissa called him after her disappearance. Several people claim Alissa told them Michael had sexually abused her or tried to abuse her. Michael denies this and maintains he is a good parent who never harmed his stepdaughter. He said the cameras were for security reasons, not so he could observe his children's activities.

In December 2008, police executed a search warrant on the home where Alissa had lived and the home across the street where her family lives now, looking for evidence in Alissa's case. They found nineteen high-caliber assault rifles, two handmade silencers, and 26 handmade explosive devices. It was the largest stockpile of weapons discovered in Phoenix Police Department history. More than 100 neighbors were temporarily evacuated from their homes as a safety precaution, and Michael was arrested on several weapons charges. He was carrying two pistols, a recording device and seven magazines of ammunition when he was arrested. Police found a 98-page document, titled "Diary of a Madman Martyr" in his home. In the document, Michael accused the International Brotherhood of Electrical Workers of being behind Alissa's abduction and murder. He wrote that he had already killed two "assassins" who were responsible for his stepdaughter's death and he would blow up the union hall in revenge and kill himself in the process.

In March 2010, Michael pleaded guilty to possessing 26 unregistered pipe bombs. He was sentenced to the maximum term of ten years in federal prison in September 2010. The sentencing judge cited reports that Michael suffers from a parnoid personality disorder that is worsening in spite of the psychiatric treatment he's received; she stated she felt he was dangerous to the public. He will be required to participate in a mental health treatment program in prison. Investigators haven't said whether Michael is a suspect in his stepdaughter's disappearance. They found many videotapes of Alissa at her home during the search, but not the one from the day she disappeared. His family set up a website advocating for him and proclaiming his innocence.

Alissa lived with her stepfather, and younger half-sister at the time of her disappearance; her mother died of cancer when she was eight years old and Michael legally adopted her. Her four older half-brothers had moved out of the family home. She had no known enemies, and it's uncharacteristic of her to leave without warning. Many agencies continue to classify her as a runaway.

Above: Michael Roy Turney, circa 2010