Detectives worked with the U.S. Marshals Service to track down Daniel Valencia-Pulido.
They arrested the 24-year-old on Tuesday and he is now booked in the Merced County jail on several charges, including murder.
Investigators found the victim, Betty Ann Choates of Seaside, on D Street near Childs Avenue back in June.
She was suffering from gunshot wounds and later died at the hospital.
There's no word yet on a possible motive.