Details of Disappearance
Valibayova was last seen in Quincy, Massachusetts on July 17, 2011. Shortly before midnight she left the restaurant where she worked, and at 12:27 a.m. she was sighted stepping off a North Quincy MBTA Red Line platform, just 200 yards from her apartment in the 10 block of Hodges Avenue. She has never been heard from again.
After her disappearance, Valibayova's apartment's door was found ajar, her bedroom furniture was out of place, and her laptop, two cellular phones and other personal items were missing. Her U.S. visa, passport and immigration papers were left behind, however, as was the whiteboard where she noted upcoming events. Her boyfriend reported her missing on July 19. That same day, Valibayova's purse, which contained her cellular phones, student identification and checkbook, were found in Dorchester, Massachusetts and turned in to the police.
Police took a second look at Valibayova's apartment three weeks after her disappearance and found a significant amount of her blood in the bedroom, enough to indicate she had been murdered. The carpet was saturated with blood and someone had attempted to clean up the stains. John D. Castonguay, a handyman in her apartment complex, was quickly identified as a suspect in her case.
A photo of Castonguay is posted with this case summary. In 1987 he was convicted of kidnapping a nine-year-old girl for the purpose of sexual assault. He was paroled in 2006 and is a registered sex offender. He told police he'd never seen or spoken to Valibayova, something her roommate denied.
In his capacity as handyman at the complex, Castonguay had master keys to all the doors and apartments. He was at her building the day of her disappearance, and he was aware that her roommate had recently moved out and she would be alone. He also admitted he cleaned her apartment after her disappearance.
Castonguay is the prime suspect in Valibayova's presumed murder, but he has never been charged in her case. He pleaded guilty to probation violation after her disappearance and served 15 months in federal prison before being released in 2015.
Since Valibayova's disappearance, she hadn't used her credit card, bank account or Facebook account, and hasn't spoken to any of her friends, her brother, or her parents in Azerbaijan, whom she normally spoke to nightly. She had put a deposit on a new apartment in Brighton, Massachusetts prior to her disappearance and was planning to move to it in September, and sublet a different apartment for August.
There's no evidence she was involved in high-risk behavior. Foul play is suspected in her case, which remains unsolved.