Wendy's

(WEN) - Get Report

doubled its reward for information about how a human finger wound up in a bowl of its chili.

The company said it will pay $100,000 to the first person offering "verifiable information into the origin of the foreign object found in a bowl of chili" last month at a Wendy's in San Jose, Calif. Wendy's, the Dublin, Ohio, hamburger chain, offered $50,000 last week for info on the case, which has been widely publicized and has hurt sales in Northern California.

"Our brand reputation has been affected nationally," President Tom Mueller said in a postclose press release Friday. "We are determined to find out what really happened in this incident."

The case has flummoxed the authorities ever since a woman reported finding the finger on March 22. At first officials focused on whether the finger came in the raw materials Wendy's used to prepare the chili.

But when police and health officials failed to find any missing digits among the workers involved in the restaurant's supply chain,

The Associated Press

reports, suspicion fell on Anna Ayala, the woman who claims to have found the finger.

The

AP

reported Friday that Ayala dropped her lawsuit against Wendy's after police started searching her Las Vegas home. Ayala has previously sued several corporations, including a former employer and

General Motors

, the

AP

reports.

"There is no credible evidence that Wendy's is the source of the foreign object," the company said in a postclose press release Friday. "We have conducted a thorough internal investigation and we remain very confident in our quality control measures. Law enforcement officers have interviewed our employees in the San Jose store and no one has suffered a hand injury. The employees passed lie detector tests. Furthermore, we confirmed with our suppliers that no hand injuries were reported in their production process. The Santa Clara Department of Environmental Health inspected the restaurant and gave us a clean bill of health."

Friday, Wendy's fell 44 cents to $38.55.