The woman, identified as 60-year-old Linda Moreno, was found in front of a home on the 300 block of N. Palm Avenue near West Alpine Street just before 7:30 p.m. Tuesday.
According to initial reports, she was found with stab wounds and slight burns from the fire. However, authorities later said she was severely beaten.
She was transported to an area hospital in serious condition but later died from her injuries.
Witnesses said the home quickly became engulfed, causing pandemonium in the neighborhood.
"Well, I heard a lot of yelling and a lot of noise at first, and three kids running down the street, talking about their grandmother, their grandmother's dead," said neighbor Frank Williams.
Authorities arrested 20-year-old Christopher Moreno, the victim's grandson, who lived at the scorched home. He was arrested on charges of murder and arson. Officials say Moreno has had numerous run-ins with the law in the past.
Investigators say Linda Moreno was visiting her grandson from Pahrump, Nev.
Police said more than one person was seen running away from the home. Descriptions were not immediately available.
Some neighbors said there was frequent police activity at the home. Investigators said the motive and cause of the victim's death hasn't been determined.
If you have any information regarding this incident, you're urged to call the Upland Police Department at (909) 946-7624.