Attacks appear to have occurred after robberies or robbery attempts on day store is marking 95th birthday

Two people were killed and three were wounded in shootings at four 7-Eleven locations in southern California early on Monday morning, authorities said, in a series of attacks that police believe may be connected.

The shootings appear to have occurred after predawn robberies or attempted robberies at the four convenience stores on July 11, or 7/11  a day when the national 7-Eleven brand is celebrating its 95th birthday by giving out free Slurpee drinks.

“Our hearts are with the victims and their loved ones,” 7-Eleven said in a statement. “We are gathering information on this terrible tragedy and working with local law enforcement.”

At least three of the four shootings are believed to be linked to the same lone gunman. It wasn’t immediately clear to investigators what prompted the shootings in the cities of Riverside, Santa Ana, Brea and La Habra, or why the violence occurred on 11 July.

“I think the only person to answer that would be the suspect,” said Ryan Railsback, a spokesperson for the Riverside police department, where the first shooting happened at about 1.50am. “There’s no way it can be a coincidence of it being 7-Eleven, July 11.”

The Riverside shooting, whose victim was in grave condition, had not yet been officially connected to the others, Railsback said, “although they all seem very, very similar”.

In that case, the gunman robbed the clerk and brandished a gun, then turned the weapon on a customer, opened fire and fled, Railsback said.

“It doesn’t appear to be any reason that the suspect shot the customer,” Railsback said. “It sounds like the clerk gave him whatever he asked for.”

The second shooting occurred at about 3.20am, about 24 miles away, in Santa Ana, authorities said.