RICHMOND, Va.—The Richmond Fire Investigations Unit are working to determine the cause and origin of a fire that engulfed William Fox Elementary School in Richmond. The Richmond Fire Department said in a post on Twitter that crews responded to a report of a building fire Friday at about 10:35 p.m. Officers arrived and encountered heavy smoke coming from the top floor of the school above the main entrance. No injuries have been reported. The fire was under control Saturday at 2:44 a.m., authorities said. “I’m heartbroken to share that Fox ES is on fire. I’m on site with Principal Jacobs. RFD is doing their very best to contain it. I’ll share more information once I have it. Please keep the Fox community in your prayers tonight,” Richmond Public Schools Superintendent Jason Kamras said on Twitter. The school was built in 1911 and has about 350 students, according to its website. …