The string of violence occurred at 7-Eleven stores in Brea, La Habra, Riverside, Upland, Santa Ana and Ontario.
LA HABRA, Calif. (KABC) -- An urgent search continued Tuesday for a suspect after two people were killed and three others wounded in a series of robberies at six 7-Eleven stores across Southern California. Authorities believe the same suspect is connected to all six of the incidents.
Los Angeles police are also examining whether a series of store robberies several days earlier in the San Fernando Valley may be connected as well.
The string of violence occurred over the course of five hours Monday, spanning multiple counties at stores in Brea, La Habra, Riverside, Upland, Santa Ana and Ontario. It wasn't immediately clear to investigators what prompted the violence.
"I think the only person to answer that would be the suspect," said Officer Ryan Railsback, a spokesperson for the Riverside Police Department.
Police in Brea responded to a 7-Eleven store at Lambert Road and North Brea Boulevard just after 4 a.m. Monday and found the store clerk shot to death in what investigators believe was a robbery.
The girlfriend of the victim who died at the Brea store identified him as Matthew Hirsch, 40.
"He was just the most caring and compassionate person and you just wouldn't expect that from somebody who looked the way that he looked," said Kristen Ewan.
The Brea store owner and his family created a GoFundMe page to help Hirsch.
According to Brea police, that shooting is believed to be related to another shooting that left at least two people injured at a 7-Eleven store in the 300 block of East Whittier Boulevard in La Habra.
A spokesperson for the Brea Police Department said those two shootings happened about 20 minutes apart.
Santa Ana police said 24-year-old Matthew Rule of Santa Ana was fatally shot at 3:25 a.m. Monday outside the 7-Eleven store in the 300 block of East 17th Street.
Police found Rule in the parking lot with a gunshot wound to the upper body, Santa Ana Police Department Sgt. Maria Lopez said. The victim was pronounced dead at the scene.
The suspect apparently never entered the store in Santa Ana and it appears he robbed Rule, Lopez said. It wasn't clear if Rule was a customer of the store or why he was there, Lopez said.
Rule's father set up a GoFundMe to help his family.
Police released surveillance images of the suspect they say is connected to the incidents in those cities. Authorities released the images in the hopes of someone recognizing the suspect, who can be seen wearing a black hooded sweatshirt with white lettering.
Meanwhile, police in Upland reported an armed robbery at a 7-Eleven store located at 2100 Block Arrow Route.
Police said the suspect - believed to be the same man connected in the previous incidents - robbed the store at around 12:37 a.m.
He allegedly stole an assortment of items, including drinks, bottled wine and between $400 and $500 in cash.
In Riverside, a customer was shot around 1:50 a.m. in what police described as an apparent robbery at a 7-Eleven store in the 5200 block of La Sierra Avenue. Police said the victim in that shooting was in grave condition.
In an update Tuesday afternoon, Riverside police confirmed the same suspect linked to the previous incidents is connected to this shooting.
In the final incident of the morning, two people, a clerk and a customer, were shot during a robbery at a store on East Whittier Boulevard.
Both of the victims in the La Habra shooting were expected to survive, officials said.
One of the La Habra shooting victims has been identified as 60-year-old Manuel "Manny" Cruz, a married father of four and grandfather of eight.
His family says he worked as a clerk on the overnight shift at the same store for 25 years.
One of his favorite parts of his shift was when friends would come to the store and they would talk about sports. He was a big Dodgers fans, and enjoyed spirited conversation with friends in Orange County who liked the Angels.
They say the customer who was shot was also a friend of Manny's. His family says first the store was robbed and then the customer was shot outside, while Manny was shot as he went outside to help.
A GoFundMe has been established to help his family.
7-Eleven said in a statement it was gathering information and working with police. "Our hearts are with the victims and their loved ones. 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. With that in mind, we encouraged stores in the Los Angeles area to close overnight," the statement said.
Below is a timeline of events of the reported incidents at various 7-Eleven stores on Monday, July 11, according to authorities.
A robbery was reported at a 7-Eleven in the 600 block of North Vine Avenue in Ontario. There were no injuries. Police say this is connected to the other robberies.
Police in Upland reported an armed robbery at a 7-Eleven store located in the 2100 Block of Arrow Route.
Riverside police reported a robbery and shooting at a 7-Eleven located at 5100 Block of La Sierra Ave. One customer was shot and remains in grave condition. Police say there was no indication the customer or store clerk did anything to provoke the gunman.
Police say a man was shot and killed in the parking lot of the 7-Eleven store at 300 Block East 17th St. in Santa Ana. The victim was later identified as Matthew Rule, 24, of Santa Ana.
Police say a clerk was shot and killed at a 7-Eleven store on Lambert Road and N. Brea Boulevard in Brea during a robbery. The victim was identified by his girlfriend as Matthew Hirsch, 40. His girlfriend Kristen Ewan described him as the "most caring and compassionate" person.
A clerk and a customer were both shot and injured during a robbery at the 7-Eleven store located at 1381 E. Whittier Blvd. in La Habra, according to police.
The Associated Press and City News Service contributed to this report.