An online weapons dealer who sold the handgun used in the Virginia Tech massacre and provided equipment in two other mass shootings has quietly closed up shop amid a flurry of complaints from customers who allege he failed to deliver orders after billing them.

Police say Eric Thompson last month abruptly closed his Green Bay, Wis.-based business, TGSCOM Inc., as they probed scores of complaints from customers in nearly every state.

TGSCOM's connections to three mass shootings have drawn national attention in recent years. Seung-Hui Cho used a .22-caliber handgun purchased through TGSCOM when he killed 32 people at Virginia Tech in April 2007. Stephen Kazmierck, who killed five people in a Northern Illinois University classroom in 2008, bought two empty magazines and a holster through a company site. George Sodini, who killed three women when he opened fire at a Pittsburgh-area health club in 2009, bought an empty magazine and a magazine loading apparatus from the company.

Thompson, who has claimed his company generates millions of dollars, has maintained he's not responsible for how people use guns, but he still has had run-ins with federal regulators and now he has dozens of people across the country angry with him.

"It gives everybody who does business online a bad name," said Dennis Johnson, a 60-year-old Web designer in Omaha, Ark. He filed a complaint with the Better Business Bureau this month and has started disparaging TGSCOM on his blog after the company billed him almost $70 for two empty magazine cartridges that never arrived.

"(His site) looked reputable," Johnson said. "The guy talked about integrity and all this crap ... pretty rude of him. And meanwhile, where is all the money going? Is he spending it?"

Thompson told the Green Bay Press-Gazette newspaper that he was doing his best to solve his problems and locate investors who could help him reopen. He said he doubted he would face criminal charges.

He didn't respond to repeated calls by The Associated Press to his cellphone and at a residential listing in Suamico, a village of about 11,000 people just north of Green Bay. His attorney also didn't return voicemail and email messages.

The business controlled a number of websites with names like topglock.com and The Gun Source that offered firearms and accessories. It was a gun lover's haven. Its still-functioning Facebook page includes multiple photographs of guns as well as shots of a cumulus cloud shaped like a handgun and a woman in a barely-there bikini top clutching two semi-automatic pistols.

Thompson defended the sales to the three mass shooters, saying any of them could have just as easily bought their gear at a Walmart. He told the AP in 2009 his company is on the forefront of the industry and generated millions of dollars in sales that year, but he wasn't "some backwoods guy just looking to make a buck off of tragedy."

Still, he visited Virginia Tech a year after the shootings there and pressed the school to allow students to carry concealed weapons. He drew support from students but the wrath of university officials and parents, who called the visit offensive and chastised him for selling products designed to kill people.

The business has been beset with problems over the last five years.

The Press-Gazette reported in 2011 that U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives records indicated an inspector found a number of violations at TGSCOM in 2009, including selling a gun without the required waiting period; selling a gun to someone who didn't answer all the required background questions; and failing to maintain proper records. The violations came on the heels of other problems the ATF detected at the company in 2007, including selling ammunition to an underage customer, the newspaper reported.

Bob Schmidt, a spokesman for the ATF's St. Paul, Minn., field office, which regulates Wisconsin firearms dealers, declined to comment, saying he is prohibited from speaking about specific dealerships.

The Wisconsin Better Business Bureau has catalogued nearly 200 complaints from consumers in 44 states between January and this week accusing the business of charging them but failing to deliver on their orders. The bureau issued an alert about the company on June 1, urging TGSCOM customers to contact their credit card companies and dispute payments to the business.

The Green Bay Police Department began investigating the business in May . At the end of the month, Lt. Kevin Warych said, Thompson closed the business. Over the last few weeks detectives have identified as many as 40 victims and have been talking with prosecutors about potential charges, Warych said. The FBI is reviewing the complaints as well, said Leonard Peace, a spokesman for the agency's Milwaukee office.

In the meantime, Thompson is going through a bitter divorce. His wife filed documents in early June in the case calling the business the largest asset in the proceeding. She questioned Thompson's "motivation and intent" in operating the business and accused him of failing to explain why he closed it.

She said in the filings she has hired an expert to assess the company's value and asked a judge to place the company under control of a third party that would analyze the situation. In a voicemail she left for the AP she said she hasn't been involved in the company for years and letting her husband run it was a "bad choice." She didn't immediately return a follow-up call.

DeAnn Perzel, the 40-year-old Chamber of Commerce president-elect in Sparta, Wis., ordered $250 worth of what she called "girly" equipment — pink laser sights, pink gun cases and pink camouflage — from TGSCOM in early January for a women's hunting raffle at the end of February. The merchandise didn't arrive in time for the raffle, she said.

Some of the products finally arrived, triggering a back-and-forth with the company to return them and get a refund that lasted for weeks, she said.

"They should be out of business," Perzel said. "They're terrible."