A California serial killer seems to be “on a mission” throughout the fatal shooting of six men and the wounding of one woman dating back to last year.

Ballistics tests and some video evidence linked the crimes in Stockton and Oakland, about 70 miles apart, police said.

“We don’t know what the motive is. What we do believe is that it’s mission-oriented,” Stockton Police Chief Stanley McFadden said Tuesday. “This person’s on a mission.”

The first fatal shooting was in Oakland in April 2021. The woman was wounded in Stockton days later. More than a year passed, then the five killings in Stockton took place between July 8 and Sept. 27, all within a radius of a few square miles, police said.

Although police would not say whether all seven shootings had been linked to the same gun, McFadden alluded to a single pistol during the news conference.

“I have absolutely no answer as to why that pistol went dormant for over 400 days,” between the April 2021 shootings and the first case this summer, the chief said.

Authorities last week announced that five men in Stockton were ambushed and shot to death, alone in the dark. On Monday, police said the two additional cases last year had been tied to those killings.

A person of interest is being sought in connection with the bloodshed — they appear on video at several of the crime scenes — but no evidence directly links them to the shootings, McFadden said. He said some of the victims were homeless and some were not.

There is a $125,000 reward for information leading to an arrest. Police are fielding hundreds of tips daily, as well as submitting additional evidence in case other crimes in the state can be connected to the spate of shootings.

The first killing targeted Juan Vasquez Serrano, 39, in Oakland at around 4:15 a.m. on April 10, 2021. He was shot multiple times, according to the Alameda County coroner’s bureau. It was not immediately clear if he was alone when he was killed.

In the nonfatal attack, the 46-year-old woman told investigators that she was inside her tent on April 16, 2021 at about 3:20 a.m. when she heard someone walking around outside.

“When she came out of her tent, she encountered someone holding a gun,” McFadden said.

The suspect fired multiple shots, wounding the woman, but she tried to defend herself by advancing toward her attacker, the chief said. The shooter lowered the gun.

“She said there were no words mentioned at all,” McFadden said.

The woman described the attacker as wearing a dark-colored hooded sweatshirt with the hood pulled up, dark-colored pants and an all-black COVID-style face mask.

In the fatal Stockton cases, none of the men were robbed or beaten before the killings, and none appeared to have known one another, Stockton Police Officer Joseph Silva said. The shootings also do not appear to be related to gangs or drugs.

The San Joaquin County Office of the Medical Examiner identified the Stockton victims as Paul Yaw, 35, who died July 8; Salvador Debudey Jr., 43, who died Aug. 11; Jonathan Hernandez Rodriguez, 21, who died Aug. 30; Juan Cruz, 52, who died Sept. 21; and Lawrence Lopez Sr., 54, who died Sept. 27.

Lopez was shot shortly before 2 a.m. in a residential area just north of downtown.

He “was just a person who was out here at the wrong place, at the wrong time, at the wrong circumstance,” his brother, Jerry Lopez, told KXTV-TV. “It’s hard to process that this has happened.”

There may even be multiple people involved in the violence.

“To be honest, we just don’t know,” Silva said. “This person or people who are out doing this, they are definitely very bold and brazen.”

Police said four of the Stockton homicide victims were walking alone and a fifth was in a parked car when they were killed in the evening or early morning.