El Cajon, California --- Two people working at a liquor store in a Broadway strip mall were shot to death -- killed by single shots in the back of the head -- inside the store late Wednesday night in what police described as a robbery gone bad.

A cousin of one of the victims discovered the man and woman face-down and bleeding inside Granada Liquor, on Broadway near Mollison Avenue, when he arrived at the liquor store to check on them around 11:30 p.m., said police Sgt. Chuck Merino.

Merino said both had been shot at least once in the back of the head.

The store's two cash registers both had been emptied, but police weren't sure whether the killer had emptied them or the cash had already been removed by the employees. The store normally closes at 11 p.m., Merino said.

As the sun came up, grieving relatives, friends and customers gathered outside the store's parking lot to tearfully console one another as an impromptu memorial of burning candles and flowers started to build.

"Why? Why? Why?" one woman, identified by a friend as one of the victims' mother, wailed repeatedly.

Sheila and Evelyn Mattia believe the woman who was killed was a member of their family and the store owners' daughter.

When the woman failed to show up for a late-night dinner Wednesday night, a cousin went to the store to look for her, said Sheila Mattia, 25, who said the woman was her cousin.

When he arrived, all the lights were off, Mattia said. He tried calling his cousin's cell phone and it just "rang and rang", she said.

He then went to get a friend who worked at the Domino's pizza outlet just a few doors down and he accompanied him inside. "That's when they found the bodies," she said.

She described the woman as a well-liked 22-year-old who was very active at the Saint Peter Chaldean Catholic Cathedral where she worked with a youth group and taught Catechism classes. She would've turned 23 on Easter Sunday.

According to Mattia, the other victim was also in his twenties and had arrived in the United States from Iraq three to six months ago. He was working two jobs to save enough money to bring the rest of his family to this country.

Sheila Mattia said she was in the store with her cousin on Tuesday night and was nervous when a rowdy group of men came into the store. She asked her cousin if she had a gun on hand but Mattia said she just laughed and said, "I deal with this all the time."

Mattia said there were no guns in the store, just a couple of baseball bats, and that her cousin was never worried that anything would happen.

She said the store would've had a lot of cash on hand as it routinely cashes checks for patrons on the first of the month.

When word of the slayings spread Wednesday night, more than 100 relatives and friends rushed to the scene and had to be held back by officers, Mattia said.

"There was a lot of crying. a lot of tears." Sheila Mattia said, adding that the local population of Chaldeans -- who are Catholics of Iraqi descent -- "is very tight and everyone knows everyone else."

Evelyn Mattia, 29, who said she was the dead woman's sister, said she had just been at the liquor store, where she frequently hangs out, Wednesday with her son. She said she always felt that the neighborhood was safe.

"My son called his auntie yesterday and invited her to his birthday party," an anguished Evelyn Mattia said. "Now she can't come." Tony Gonzales of El Cajon said he regularly cashed checks at Granada Liquor and knew both victims.

"They were really good people, nice to everybody," said Gonzales, 55.

The California Independent Grocers and Convenience Stores Association, in conjunction with San Diego County Crime Stoppers, is offering a $20,000 reward for information leading to the arrest and conviction of whoever is responsible for the killings, said association president Auday Arabo.

Arabo said the owners of Granada Liquor were members of the association and that the family owns several stores in the area.

He also said that the woman who was killed was going to leave early on Wednesday but for some reason, changed her mind.

"We won't stand for anyone to come in and do this to one of our members," Arabo said. "This is so heart-wrenching. A young girl is dead, and she was just doing what her family wanted her to do.

"The person that did this is a coward, an animal."

By Debbi Farr Baker and Greg Gross
San Diego Union Tribune