Gennifer Quick knew something was up the minute she hit the lights.

The inside sales representative was closing up shop at the Glass Doctor in Martell the evening before July 4. She had just turned off the main lights overhead, so the only illumination was coming from the fluorescent glow beneath the counter. When Quick looked down, she noticed something funny about the $100 bills in her possession: It wasn't Benjamin Franklin staring back at her but old, honest Abe.

The custom glass repair and installation shop was one of several businesses reportedly hit by a counterfeit ring broken up in Lodi this week. Six people have so far been arrested, including the suspect in the Glass Doctor case and a man who was arrested trying to pass a counterfeit bill at the Lowe's in Lodi.

From April to mid-July, the Amador County Sheriff's Office has received 42 reports of counterfeit money, 11 of those reports involving fake $100 bills. The Wal-Mart in Martell reported 10 fake bills last week and 29 reports have come from the Jackson Rancheria Casino, said sheriff's Lt. Drew Stidger.

Whether there's a connection with the Lodi ring is not yet apparent. Stidger said Amador detectives would be exchanging information with Lodi police to determine if there is a link. Scott Gillingham, the resident agent in charge of the U.S. Secret Service's Sacramento field office, whose coverage area extends to the Oregon border, would only say an agent was working with the Lodi Police Department.

On Tuesday, 32-year-old Clinton Irons was one of several suspects arrested by Lodi police after attempting to pass a fake $100 bill at the local Lowe's. Quick said she was contacted by Lodi police Tuesday morning about the arrest of the woman who visited the store almost two weeks earlier. The woman, who has been identified as Holly Haworth of Lodi, reportedly tried to pass three fake $100 bills at the glass repair shop on July 3, when she pre-paid a $300 estimate for having a side window in her car replaced. Haworth claimed it was shattered while she was at the Jackson Rancheria Casino, according to Lodi Det. Nick Sareeram. Quick realized the bills were doctored when the fluorescent lights illuminated the actual water mark later that night.

"I'm just very grateful Gennifer was able to recognize that it was a loss," said store owner Mark Borchin.

The sheriff's office is also investigating at least one reported incident at Wal-Mart last week. A woman claimed she cashed her $600 economic stimulus check at Bank of America, deposited $100 and took the rest to the department store to do some shopping. A clerk spotted the suspicious currency and contacted the sheriff's office. The Bank of America in Jackson couldn't be reached by phone and Wal-Mart declined an interview.

"We are working closely with the investigating authorities and will continue to cooperate in the investigation," media relations representative Ashley Hardy said in a phone message. "But any further comment or update would best be served coming from them."

How far the recent spate of counterfeiting extends remained unclear. Sareeram said it's difficult to track how much phony money is actually circulating or if more people were involved in the Lodi ring. Investigators found a number of doctored bills at one of the homes they searched and have identified a circle of acquaintances who had received the bills. Whether they were the actual counterfeiters is still under investigation.

"Unfortunately, it crossed county lines and became Amador's problem," Sareeram said.

The Amador County Chamber of Commerce and Visitors Bureau received several inquiries. Gillingham said the crimes were not necessarily linked, though he added that the Secret Service would look for any trends. "A few passes in (one) area ... is not necessarily the same thing," Gillingham explained, adding that his field office receives reports of counterfeit notes from across the state.

Stidger said the sheriff's office has seen an increase in reports the past three-and-a-half months, but couldn't speculate about whether it was due to the Lodi ring or a bad economy. He did say the quality of the forgeries was impressive. "These are really good bills. Whoever's doing these, it's very professionally done," he said.

Typically, when there is a significant amount of counterfeit bills cycling through an area, Gillingham said the Secret Service will distribute fliers to merchants notifying them what to look for. "We're not there yet and it may not warrant that," he said. Depending on the circumstances, Gillingham said the U.S. Attorney's Office could be brought in for federal prosecution.

Meanwhile, Stidger has some advice for a concerned public. "People who are taking $100 bills or $20 bills should be examining them regularly," he said. Tips and fliers for download or print can be found at www.secretservice.com.

Borchin and his employees did what they could, contacting law enforcement and placing a mechanic's lien on the vehicle. Borchin also made copies of receipts found in the car and turned them over to Lodi police. Among them were a $500 receipt from an electronics store and a $200 receipt from a department store. "We were very fortunate," said Borchin. "In these hard times, we don't need any more challenges."