On Monday, or 7-11, several robberies and at least four shootings, two of them fatal, were reported at 7-Eleven stores across the greater Los Angeles area.
Authorities are searching for a suspect linked to three of the incidents.
And police in Ontario and Riverside are investigating whether the same person is involved in crimes in their cities.
In the first incident, which occurred around midnight, the suspect allegedly displayed a handgun and demanded money from a store clerk. Described as a Black man wearing dark clothing and a dark mask, he didn't fire and the worker wasn't injured, the Ontario Police Department said.
Another incident occurred at a 7-Eleven location in nearby Upland, California, just before 2 a.m. where a man brandished a gun and stole $400 to $500 in cash, according to NBC Los Angeles. No shots were fired before the suspect fled, the station reported.
At about 3 a.m. and roughly 20 miles away, a customer at a 7-Eleven in Riverside was shot after a man entered the store and robbed the clerk, Riverside police spokesman Ryan Railsback said.
The victim, a customer in his mid-40s, remained in "grave" condition late Monday afternoon, Railsback said.
The other robberies and shootings occurred in Santa Ana, Brea and La Habra from 3:20 a.m. to 4:55 a.m., authorities said.
Sgt. Maria Lopez, a Santa Ana police spokeswoman, said it wasn't clear whether its "being a 7-Eleven on 7/11 has any relation to why he did it,” adding, “It's hard for me to say."
The company — which was offering free frozen drinks Monday for "Slurpee Day" — urged its stores in the Los Angeles area to close.
"Our hearts are with the victims and their loved ones," the company said. "We are gathering information on this terrible tragedy and working with local law enforcement. Right now, our focus is on Franchisee, associate and customer safety."
The victim in the Santa Ana shooting was found in a parking lot outside the 7-Eleven after the shooting was reported at 3:20 a.m., Lopez said. The victim, who hasn’t been identified, was shot once in the head and pronounced dead at the scene, NBC Los Angeles reported.
"We don't believe he was an employee," Lopez said. "He may have been either walking or he was a potential customer."
Detectives linked the suspect to the other shootings after they saw a security photo released by authorities in Brea, about 13 miles north, Lopez said.
The security photo in Brea shows a man in a black sweatshirt with green and white letter that appears identical to a man seen in security footage from the Upland robbery, according to NBC Los Angeles.
In that shooting, officers responded after 4 a.m. to a report of a 7-Eleven clerk who had been fatally shot during a robbery, the police department said on Twitter. The clerk, who hasn’t been identified, was pronounced dead at the scene.
"Our hearts go out to the families of that person," Brea Police Capt. Phil Rodriguez said at a briefing. "Please know we're thinking about you."
Additional details about the shooting weren't immediately available. Rodriguez said authorities planned to warn area 7-Eleven stores to take additional precautions.
In a fourth shooting in the nearby city of La Habra, officers found two people who had been shot after a robbery was reported just before 5 a.m., Sgt. Sumner Bohee, a police spokesman, told reporters.
The victims were taken to a hospital, he said. Their conditions weren't immediately known.
"We feel confident it's the same suspect" in the Brea and La Habra shootings, Rodriguez said.