A 20-year-old Richmond man was arrested Monday after a coworker was fatally stabbed at a business in San Rafael’s Northgate One Shopping Center, police said. Officers were called shortly after 1 p.m. to the 700 block of Las Gallinas Avenue for a report of an unconscious man who appeared to have fallen. Responders found the victim with an apparent stab wound. Police said he had left the business through a rear exit before collapsing outside and later died at a hospital. Investigators identified the victim as an employee at a business in the shopping center based on his clothing. Police said the victim and suspect, identified as Justin Amilcar Gutierrez-Navarette, were coworkers and had been involved in an ongoing dispute that escalated into a fight and stabbing. The victim’s identity and the business’s name have not been released. As the investigation began, Gutierrez-Navarette contacted police and arranged to surrender. After an interview, he was arrested and booked into jail on a murder charge, police said. Authorities have not released further details about the dispute. The charge is an allegation, and the case remains under investigation. Anyone with information can contact the San Rafael Police Department at 415-485-3000.