Three more cases of E. coli were identified among customers of an Orange County restaurant, bringing the number of people sickened to 10, reports the Associated Press. Interviews with all 10 people confirmed they ate at a restaurant in the city of Lake Forest on March 23 or 24, the Orange County Health Agency said in a statement.

"We have not yet identified the source of the infections, and our investigation is continuing," the agency said.

The latest cases were confirmed a day after health officials announced that tests showed the first seven cases all had the same strain of E. coli in common, indicating a common source of infection. One of the earlier cases, a 12-year-old girl, remains in intensive care at Children’s Hospital of Orange County, said county health information officer Deanne Thompson.

The restaurant has remained open. Health inspectors concluded its food and conditions were safe.