Investigators said Tuesday they need the public’s help solving a series of four deadly shootings in San Bernardino over the past year that they believe are related, even though some of them were apparently random attacks.

The first killing claimed the life of 24-year-old middle school teacher Nancy Magaña as she sat in a parked truck with her boyfriend and 5-year-old son outside the Delmann Heights Recreation Center on Aug. 17, according to San Bernardino police.

The second incident occurred a month later, on Sept. 14, as a father was driving with his toddler child on Cajon Boulevard, a few blocks away from Delmann Heights. Another motorist shot the father — 21-year-old Detrell Page of Colton — in the back of his head, resulting in a crash that left 2-year-old Dekorro Page dead. Detrell Page was left in critical condition but survived.

Two other shootings occurred within a few days last month.

The morning of Jan. 19, 24-year-old Lemon Hamilton of San Bernardino was found fatally shot near the corner of Meridian Avenue and Spruce Street. A second victim, 20-year-old Rialto resident Jesus Valencia, later arrived at a hospital and was treated for a wound, officials said.

And the afternoon of Jan. 21, officers found two men shot dead in the area of Hanford Street and Grand Avenue. They were both San Bernardino residents, 24-year-old Israel Delatorre and 33-year-old Daniel Melendrez, according to police.

Detectives believe the shootings are related because they all occurred on the city’s west side, with the first two in very close proximity.

It’s possible the shooter or shooters knew some of the victims, but it’s also possible some of the incidents were random attacks part of a gang initiation — especially with Magaña’s case, Sgt. Al Tello said in a Tuesday news briefing.

The recreation center parking lot where the schoolteacher was shot is a “high gang area,” the sergeant said.

“They had been out earlier that evening. We actually tracked where they were earlier that day — (Ontario) Mills mall and such — and then they ended up parking there for a few minutes before they went to her house, which was close by,” Tello said. “It is a gang area, so it was not safe to park there.”

Tello says no words were exchanged between Magaña or her boyfriend and the gunman before he opened fire on the pickup’s driver’s side. The boyfriend told authorities he did not recognize the shooter.

Although the attacks could possibly be gang-related and they occurred in the same part of town, Interim Police Chief Eric McBride says he isn’t ready to associate the neighborhood or crimes with any specific gang.

“It’s often it’s said that 90% of your crime is committed by 10% of your population, and I think that kind of fits what’s going on here,” McBride said.