Police in San Bernardino, California, say they believe that if they can crack just one of four brutal, unsolved shootings over the last six months, they will solve them all.

The killing spree, which is believed to be gang-related, started at around 2 a.m. on Aug. 17, 2019, when Nancy Magana, a 25-year-old middle-school teacher, was shot while sitting in a pickup truck with her boyfriend and 5-year-old son in west San Bernardino. Surveillance footage shows a group of unidentified men driving a light-colored sedan near the truck, which was stopped in the parking lot of a local park. Then two of the men got out of the car and, without speaking to each other or anyone in the vehicle, one man took out a high-powered weapon and shot directly through the driver’s side window. Magana’s boyfriend and son survived, but the teacher died at a hospital.

“No words were exchanged between Magana and [the people in] that vehicle,” Sgt. Al Tello with San Bernardino police said at the time. “Someone walked up from that car and opened fire on the driver’s side, striking her through no fault of her own. She was just sitting there with her boyfriend.”

Then, nearly a month later, on Sept. 14 just before 7 p.m., about a mile from where the first shooting occurred, a man driving a red Toyota Camry with his 2-year-old daughter was shot by men in a light-colored sedan while driving down a street. He crashed his car into a guard rail. He survived, but the toddler did not.

Another similar assassination-style shooting occurred before 6 a.m. on Jan. 19, when officers found 24-year-old Lemon Hamilton dead in the middle of a street in west San Bernardino after being shot by a group of men in a car. A short time later, a second victim, who had apparently fled the scene, showed up at a hospital for treatment. Police believe in that incident, gunfire was exchanged with the group of unidentified shooters.

The fourth shooting came on Jan. 21 when police found Israel De La Torre, 24, dead on the ground beside the driver’s side of his black 2007 GMC Yukon. A 33-year-old man who was with La Torre at the time he was killed was found dead a few blocks away, likely trying to flee the scene, authorities said. Again, surveillance footage shows a group of men in a car dropping off the killers who ambushed their victims before meeting the getaway car and fleeing the scene after the victims were dead.

Police say they have only just connected the five deaths, which all occurred on the same side of San Bernardino. They are appealing to the public for witnesses or anyone who might know who the gang of killers is. “There are people out there that saw these homicides, saw these shootings, that saw what happened, and we need those folks to come forward,” Interim Police Chief Eric McBride said at a news conference Tuesday.

Since the killings began, police have bolstered their defense teams in five San Bernardino neighborhoods that have traditionally been vulnerable to gang violence. Officers have set up 300 community meetings as part of an outreach program in hopes of penetrating the wall of silence surrounding the crimes. Since beefing up the police force in the area, McBride said the force coincidentally solved a slew of other homicides, raising the rate of arrests in random homicides from 46 percent in the first half of 2019 to 78 percent as of January 2020.