Napa County District Attorney Allison Haley on Thursday announced the filing of murder charges against Vallejo resident John Richard Wesley Nicholson Jr., age 22, in connection with the shooting deaths of a 19-year-old woman and a 17-year-old girl that occurred on the evening of April 13 in the city of Napa.

The defendant is accused of shooting the two victims during an altercation that took place along the 400 block of Riverside Drive at 8:10 p.m., Saturday.

In addition to the two murder charges filed against Nicholson, he is charged with the special circumstance of multiple murder. Additionally, he is charged with the special allegation of personal and intentional discharge of a firearm causing death.

It is further alleged that the crimes involved great bodily harm and involving a high degree of cruelty, viciousness and callousness; that the crimes were carried out with planning, sophistication, and professionalism; and that the defendant engaged in violent conduct that indicates a significant danger to society.

Nicholson last appeared in court on Wednesday afternoon for an arraignment hearing in which he did not enter a plea and was assigned a public defender.

In addition to the charges against the defendant, the Napa County District Attorney’s Office is investigating charges against two suspected accomplices – Santa Rosa residents Jessica Whitten and Judith Adolph, both 19 – who were also arrested in connection with the murders.

Further details regarding this case will not be released at this time as Napa County Deputy District Attorney Agnes Dziadur and Napa County District Attorney Investigator Nick Conrad, along with the assistance of the Napa Police Department, prepare the case against the defendant on behalf of the People.