The tweet came from Philadelphia, alerting Pennsylvania Attorney General Josh Shapiro that a supermarket was selling a 36-roll package of toilet paper for $39.99.

Add that to the list of hundreds of cases of alleged price gouging now under investigation by Shapiro’s office. Those rolls of toilet paper join paper towels, cleaning supplies, hand sanitizer, disinfectant wipes, and other items. One pharmacy in Montgomery County was charging $25 for face masks.

Shapiro, who declined to identify the merchants while his office investigates, said the state’s Price Gouging Act comes into play when merchants charge “an amount which represents an unconscionably excessive price" while the state is under an emergency disaster declaration.

Gov. Tom Wolf signed that declaration for the coronavirus crisis on March 6.

“In Pennsylvania, it has been interpreted as exceeding 20% of the average price over the seven preceding days,” Shapiro said of price gouging. But, he said, “I don’t want the people of Pennsylvania to worry about the legal definition. They sort of know if when they see it.”

Shapiro asks consumers who believe they’ve been victimized to email his office — pricegouging@attorneygeneral.gov — with the name and location of the store, the product, and the price. They can also send pictures.

Shapiro’s office tweeted Monday morning that it had received more than 700 complaints about price gouging. By the afternoon, that had increased to 831 complaints.

The majority of those complaints came from Southeastern Pennsylvania, with Shapiro noting those counties have been “the most impacted” by the virus. He expects reported incidents to spread as government ordered shutdowns reach other parts of the state.

“I anticipate over the coming days as the governor’s directives extend beyond Southeastern Pennsylvania that we will receive tips from all across the commonwealth,” he said.

Shapiro’s first order of business is putting a stop to it.

“Our focus, when we get a tip, is on chasing it down, contacting the merchant, and making clear to them that we’re aware, and we want them to cut it out,” he said. “And we’re seeing stores lower their prices as a result of our outreach.”

Merchants that continue to charge inflated prices receive a cease-and-desist letter, along with a subpoena for prices before the emergency disaster declaration. The Attorney General’s Office can petition a court to close the retailer. It can also seek civil penalties of up to $10,000 per violation.

New Jersey and Delaware are also asking consumers to report suspected price gouging. In those states, boosting the cost of a product by more than 10% during a declared state of emergency amounts to price gouging.

New Jersey Attorney General Gurbir S. Gerwal announced last week that his office is cracking down on the practice while also targeting merchants hawking products with “misleading claims” that they can treat or prevent the virus. Consumers in that state can call 973-504-6240 to file complaints.

New Jersey Gov. Phil Murphy echoed that, promising “zero tolerance for price gouging."

And the Delaware Department of Justice is asking consumers to report issues by calling 302-577-8600.

You can also report price gouging to The Inquirer by filing out this form online.