Police Make Arrests in Homicide Investigation

Published on March 10, 2026

Contact: FCPSMedia@fortcollins.gov

**Update** Police Investigate Homicide in the 2600 block of Illinois Drive

Detectives have been working continuously to identify, locate, and arrest the suspects in this case. Through the investigation, the three suspects identified were Zackary WORRELL (Dob: 03/26/1999), Aaron MACK (Dob: 03/06/1993), and Brittany King (Dob: 01/11/1986). King was contacted and arrested in the 3800 block of E Mulberry Street. When detectives attempted to contact WORRELL, he barricaded in a hotel room also in the 3800 block of E Mulberry Street. Due to this, the Larimer County Sheriff’s Office’s All Hazards Crisis Response Team was paged to assist, but WORRELL exited on his own. MACK was arrested from an apartment in the 2500 block of Joseph Allen Drive.

They were arrested and booked into the Larimer County Jail on the following charges:

Zackary WORRELL: Murder in the First Degree - After Deliberation; class 1 felony; §18-3-102(1)(a)

- Murder in the Second Degree - Felony Murder; class 2 felony; §18-3-103 (1)(b)

- Aggravated Robbery; class 3 felony; §18-4-302 (1)(b)

- Conspiracy to commit Aggravated Robbery; class 4 felony; §18-2-201 and §18-4-302(1)(b)

- Tampering with Physical Evidence; class 6 felony; §18-8-610 (1)(a)(3)(a)

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Aaron Mack: Murder in the Second Degree - Felony Murder; class 2 felony; §18-3-103 (1)(b)

- Aggravated Robbery; class 3 felony; §18-4-302 (1)(b)

- Conspiracy to commit Aggravated Robbery; class 4 felony; §18-2-201 and §18-4-302(1)(b)

- Accessory to Crime; class 4 felony; §18-8-105 (1)(3)

- Tampering with Physical Evidence; class 6 felony; §18-8-610 (1)(a)(3)(a)

- Criminal Mischief; class 2 misdemeanor; §18-4-501 (1)(4)(b)

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Brittany King: Murder in the Second Degree - Felony Murder; class 2 felony; §18-3-103 (1)(b)

- Aggravated Robbery; class 3 felony; §18-4-302 (1)(b)

- Conspiracy to commit Aggravated Robbery; class 4 felony; §18-2-201 and §18-4-302(1)(b)

- Accessory to Crime; class 4 felony; §18-8-105 (1)(3)

Police have reason to believe that at least one of the suspects knew the victim before this incident.

“I’m grateful for the dedication and work of our entire Criminal Investigations Division here at Fort Collins Police Services. The work of these detectives is what lead to this resolution, and we will continue to work to support the family of the victim as this case proceeds through the criminal justice system,” said Assistant Chief Frank Barrett who oversees the Fort Collins Police Criminal Investigations Division.

Anyone who witnessed the incident or has additional information that could aid the investigation, please contact FCPS Tip Line at (970) 416-2825 or tipsline@fcgov.com. People who want to remain anonymous can contact Crime Stoppers of Larimer County at (970) 221-6868 or www.stopcriminals.org.

No further information will be released at this time. While all the suspects in this case are in custody, it is still an open and active investigation. Charges are merely an accusation by law enforcement, and the suspects must be presumed innocent until proven guilty in court.

Original Press Release

On Sunday, March 8, 2026, at approximately 10:13 a.m., Fort Collins Police Services (FCPS) was dispatched to the 2600 block of Illinois Drive on the report of a male slumped over in a vehicle.

Upon arrival at the scene, officers found a deceased male victim inside of a parked vehicle. The incident is being investigated as a homicide. At this time, investigators do not believe there is an active threat to the community.

The name of the deceased will be released by the Larimer County Coroner’s Office upon notification of next-of-kin.

“Violence like this has a profound impact on our community,” said Assistant Chief Frank Barrett, who oversees the FCPS Criminal Investigations Division. “Our investigators are working tirelessly to determine what happened and identify those responsible. If anyone has information, we urge them to come forward. Tips from the community can be critical in cases like this.”

No other information is available as the matter is still an active investigation.