Vallejo resident John Nicholson, Jr., 22, was arrested Monday after investigators identified him as the suspect in the killing of a 19-year-old woman and a 17-year-old girl in the city of Napa.
Nicholson is accused of shooting the two during an altercation in the 400 block of Riverside Drive between Laurel and Oak streets on Saturday night.
INTERACTIVE: Take a look at the ABC7 Neighborhood Safety Tracker
RELATED: 2 women shot and killed in Napa, police say
2 women shot and killed in Napa, police say
Two other women were arrested in connection to the case as well-- Santa Rosa residents Jessica Whitten and Judith Adolph, both 19.
In addition to murder charges, Nicholson is charged with the special circumstance of alleged multiple murder. He is also charged with the special allegation of personal and intentional discharge of a firearm causing death. Prosecutors allege that he commmitted crimes that involved great bodily harm and a "high degree of cruelty, viciousness and callousness," and that the crimes were "carried out with planning, sophistication professionalism."
RELATED: 3 arrested after 2 young women shot and killed in Napa, police say
Nicholson appeared in court Wednesday for his arraignment, where he did not enter a plea, according to prosecutors.
Police and prosecutors are not releasing more information about the shootings at this time.