LOS ANGELES (AP) — The 7-Eleven convenience store chain offered $100,000 Wednesday leading to the arrest and conviction of a masked gunman suspected of robbing six Southern California stores, killing two people and wounding three others. A clerk, Matthew Hirsch, 40, was shot and killed at a Brea store and Matthew Rule, 24, was gunned down in the parking lot of a Santa Ana store during a five-hour string of holdups Monday morning. Police in Ontario, Upland, Riverside and La Habra have said they believe 7-Eleven robberies there also are linked.