Officer Michele Gigante says a Sacramento County sheriff's deputy found 51-year-old Michael Williams on Tuesday.
Police say Williams is suspected of fatally stabbing his wife, 48-year-old Tanganyika (Tan-gah-NEE-kah) Williams, whose body was found July 8 on a Sacramento street.
Barnes pleaded for help from the public, using his Twitter and Instagram accounts to publicize the manhunt.
Gigante says Williams was found after a tip from a citizen who saw his description in news coverage.
Police say Williams was transient and thought to be hiding in south Sacramento.
He was arrested less than five miles from the crime scene.