Luke Kang, 26, is under arrest. Investigators did not say how he and the victim are related. The woman was in her 50s.
The attack allegedly took place Wednesday night on the 11500 block of Stoneridge Drive in Rancho Cucamonga. The woman was hospitalized, where she later died.
Kang has served prison time three years ago for assault with a deadly weapon, according to authorities.
Late Thursday afternoon police were still on scene collecting evidence and talking with neighbors.
Brian Ciszek lives behind the home where the beating allegedly happened. He says he only spoke with the suspect once, a while ago, when he thought something might be burning in their backyard.
"He was really standoffish and didn't say anything, and didn't look at me in the eyes, but called for the other individual that was living there, and then she came out and explained they had purchased a smoker," said Ciszek.
Another neighbor, Robert Groves, said he remembers a pretty big argument at the home about a month ago.
"He was threatening his father at the cul-de-sac with a golf club," said Groves.
Two sets of golf clubs could be seen in the house's garage Thursday, and a box of golf shoes with the suspect's name on it.
"The homicide investigators that are currently working on this case have not released any information on the weapon used," said San Bernardino County Sheriff's Spokeswoman Cindy Bachman.
While neighbors say the suspect lived at the home with his mother, father and brother, police aren't saying much about their relationship.
"The suspect and the victim both reside at the Stoneridge address, but the relationship between the two of them has not yet been confirmed," said Bachman.
Kang was booked at the West Valley Detention Center on $1 million bond.