Diol–Beye family murders

Background

The victims were members of two Senegalese immigrant families sharing a home at 5312 Truckee Street in the Green Valley Ranch neighborhood of northeastern Denver, Colorado. Nine people lived in the house, including the families of Amadou Sow and Djibril "Djiby" Diol.

The attack originated from an unrelated robbery: 16-year-old Kevin Bui had been robbed of his phone and cash in July 2020 while attempting to buy a gun. Using Apple's Find My feature, Bui traced his stolen phone to 5312 Truckee Street, unaware that such location tracking can be inaccurate by hundreds of miles — meaning the address had no actual connection to the theft.

The Attack

On the night of August 4–5, 2020, Bui recruited two friends, 15-year-old Gavin Seymour and 14-year-old Dillon Siebert, to help him carry out revenge. The three bought masks from a Party City store and gasoline, then drove to the Truckee Street address, arriving around 1:00 AM on August 5. Finding the back door unlocked, they entered the house, doused the living room with gasoline, and set it on fire. A neighbor's security camera recorded the three fleeing the scene at 2:40 AM as flames erupted from the house.

Victims

Five people died of smoke inhalation: Djibril Diol (29, a civil engineer), his wife Adja Diol (23), their daughter Khadija Diol (1, two months short of her second birthday), Djibril's sister Hassan Diol (25), and Hassan's daughter Hawa Beye (7 months old). Three others survived by jumping from second-story windows: Amadou Sow, who suffered a fractured foot; his wife Hawa Ka, who sustained spinal fractures; and their 10-year-old daughter, Adama.

Investigation and Legal Proceedings

Denver Police Department detectives Neil Baker and Ernest Sandoval led the investigation, which was initially hampered by limited evidence. Investigators used cell tower data, geofence warrants to Google, and ultimately a reverse keyword search warrant compelling Google to identify users who had searched variations of "5312 Truckee Street" in the 15 days before the fire. This search led to the identification of Bui and his co-conspirators, who were arrested on January 27, 2021.

Defense attorneys challenged the reverse keyword warrant as an unconstitutional "digital dragnet." In October 2023, the Colorado Supreme Court ruled the warrant was "constitutionally defective" for lacking individualized probable cause, but held it was ultimately lawful due to its narrow parameters and computer-based execution.

Sentences

All three defendants accepted plea bargains. Kevin Bui, tried as an adult, pleaded guilty to two counts of second-degree murder in May 2024 and was sentenced to 60 years in prison in July 2024, with parole eligibility after 41 years. Gavin Seymour, tried as an adult, pleaded guilty to one count of second-degree murder and was sentenced in March 2024 to 40 years, with parole eligibility after 26 years. Dillon Siebert, tried as a juvenile, pleaded guilty to second-degree murder in 2023 and received a combined 10-year sentence (3 years juvenile detention followed by 7 years in the Colorado Youthful Offender System), with parole eligibility after 6 years.