Brownlee is being charged for the alleged murder of Juan Alexander Vasquez, out of Alameda County, and a new Alameda County victim, Mervin Harmon. Additionally, the DA is charging Wesley for allegedly murdering Paul Yaw and Salvador Debudey, Jr., and the attempted murder of Natasha LaTour, all out of San Joaquin County.
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The Harmon case is new, but Wesley had previously been suspected of the four other crimes yet hadn't been charged.
The DA's Office has not yet specifically commented on the new charges, but District Attorney Tori Verber Salazar promised "justice for these victims."
Brownlee was arrested in October on suspicion of the shooting deaths of six people. He has already been charged for the deaths of Jonathan Rodriguez, 21, Juan Carlos Carranza-Cruz, 52, and Lawrence Lopez, 54.
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Victim LaTour is the only known survivor of the serial shootings.
A convicted drug offender, Brownlee was barred from owning a gun and he allegedly used an unregistered "ghost gun" to carry out at least some of the slayings, police said in October after his arrest.
In January 1999, Brownlee had been sentenced to two years in prison in Alameda County, which encompasses the city of Oakland, for possessing and selling a controlled substance, the California corrections department said. He was released on parole in August 1999 after serving seven months.
Brownlee was again convicted in Alameda County in December 2001 and sentenced to three years for the same crime. He was paroled in May 2003 and discharged three years later.
The Associated Press contributed to this report.