Four additional murder charges were filed Tuesday against a Northern California man who was arrested in October for a series of killings.

Wesley Brownlee, 43, of Stockton, California, has been charged with a total of seven counts of murder and one count of attempted murder. Prosecutors said Brownlee used a "ghost gun" in a murder spree that stretched from April 2021 to September 2022.

A new filing shows that prosecutors believe that Brownlee, who worked as a trucker in Stockton at the time of his arrest, killed another man, Mervin Harmon, in Alameda County on April 16, 2021. On the same night, Brownlee allegedly drove over 70 miles and assaulted a woman, Natasha LaTour, 46, who is the only known survivor of Brownlee's killing spree.

LaTour reported that she was sleeping in a tent in Stockton when she heard someone outside. She says she exited the tent and saw a man dressed in all black who began shooting at her several times before leaving without saying anything. LaTour survived after being found by passersby and rushed to the hospital.

Brownlee has also been charged with the murder of Juan Alexander Vasquez, 39, who was found dead in Oakland on April 10, 2021. Vasquez is believed to be Brownlee's first victim, according to the prosecution's timeline.

Brownlee was charged with the murders of five other victims -- Paul Alexander Yaw, 35; Salvador William Dubedy Jr., 43; Jonathan Rodriguez Hernandez, 21; Juan Carlos Carranza-Cruz, 52; and Lawrence Lopez, 54.

Police arrested Brownlee on Oct. 15 on suspicion of murder. Investigators say they began following him after they received a tip. When arrested, Brownlee was driving while armed and dressed in all black. Police believe he was planning another murder.

"He was on a mission to kill. He was out hunting," Stockton police chief Stanley McFadden said in a statement. "We are sure we stopped another killing."

Brownlee is being held without bail and is due to be arraigned in court on Jan. 3.