Johnny Brown was arrested on suspicion of murder, elder abuse, burglary, and robbery, sheriff's officials said.
VIDEO: 4th suspect in elderly SJ woman's beating death says he's innocent
Sheriff's officials did not disclose details about Brown's a 19-year-old or about his involvement.
Brown is the fourth suspect to be arrested in connection with the Sept. 12 murder of Floavis Douglas, also known as Miss Flo to her friends and family.
Douglas was beaten and kicked during the alleged robbery at her home near San Jose's Alum Rock neighborhood, in which her jewelry and car were stolen. Douglas later died at a hospital on Oct. 8.
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Days after the initial beating and robbery, investigators identified and arrested Zachary Cuen on suspicion of murder.
Months later, investigators arrested Cuen's then-girlfriend Jennifer Hernandez Jimenez on suspicion of concealing evidence in the alleged homicide, according to sheriff's officials.
In May, 20-year-old Perla Arreola also was arrested on suspicion of being an accessory in Douglas' killing.
#MORE: Sinica Santos, mom of Johnny Brown, is accused of helping her son elude detectives investigating the case. Arrested for accessory.— Chris Nguyen ABC7 (@ChrisNguyenTV) July 26, 2017