The Justice Department is warning people hoarding masks, gowns and medication touted by President Trump as a possible coronavirus treatment that they are in the crosshairs of federal prosecutors cracking down on covid-19 profiteering.

Attorney General William P. Barr this week made his first appearance at a White House coronavirus briefing, standing alongside Trump as he warned potential hoarders of medical masks, “you will be hearing a knock on your door.”

A day later, the two U.S. attorneys in Ohio aimed a public statement at a different kind of stockpiler: physicians who are prescribing anti-viral medications to healthy friends or associates because there is some anecdotal evidence the drugs could treat the novel coronavirus.

“If there’s a shortage that’s driven by panic in the medical profession, that cannot stand,” said Justin Herdman, the U.S. attorney in Cleveland. “So we are committed to going after this.”

The investigative efforts, so far, are nascent. Federal prosecutors have not charged anyone with crimes stemming from coronavirus-related hoarding, though they have brought a civil case against a website claiming to distribute vaccines, which do not exist. Officials said the scope of the problem is still largely unknown.

But Barr said at the White House that officials had “already initiated investigations of activities that are disrupting the supply chain and suggestive of hoarding,” as well as directing each of the U.S. attorney’s offices to designate lead prosecutors in their offices to handle any cases that might be brought.

In a memo Tuesday, Barr wrote that he was creating a task force, led by New Jersey U.S. Attorney Craig Carpenito, to fight hoarding and price gouging.

“We will not tolerate bad actors who treat the crisis as an opportunity to get rich quick,” Barr wrote.

Health officials across the country have complained that they are facing a possible shortage of supplies — especially protective masks — needed to treat patients with covid-19, the respiratory disease caused by the coronavirus. Trump has invoked the Defense Production Act to encourage companies to produce masks and other equipment, though he has not fully leveraged the law.

On Monday, Barr announced Trump would use a different section of the act to help prohibit hoarding. The secretary of the Department of Health and Human Services, Barr said, will now be able to designate certain medical supplies as scarce, thus making stockpiling illegal.

“We’re talking about people hoarding these goods and materials on an industrial scale for the purpose of manipulating the market and ultimately driving windfall profits,” Barr said. “If you have a big supply of toilet paper in your house, this is not something you have to worry about. But if you are sitting on a warehouse with masks, surgical masks, you will be hearing a knock on your door.”

Similarly, pharmacists have raised concerns about a shortage of drugs — especially chloroquine and hydroxychloroquine — which have shown some early promise in treating the coronavirus.

The drugs have a prominent endorser: Trump, who on Twitter and at White House briefings has expressed hope in their success even though they have not been thoroughly scientifically tested as an effective coronavirus treatment. The president has heralded chloroquine — perhaps in combination with the antibiotic azithromycin — as a potential “game-changer” and asserted that patients have little to lose in trying the medications.

The result, pharmacists say, has been a run on the drugs, which are typically used to treat lupus, malaria and rheumatoid arthritis.

The demand is mostly legitimate: Doctors and hospitals saw news reports and figured it was worth having a stock on hand.

“I think initially more physicians were giving it a try than might be called for because you want your patients to get well,” said Ernie E. Boyd, executive director of the Ohio Pharmacists Association. “Physicians are allowed to use drugs for off-label uses, so if a physician’s magazine said we had effectiveness in this rare disease, a physician is welcome to give something a shot.”

But Boyd and others said their organizations had fielded reports of physicians trying to hoard the drugs or direct them to friends or family — even those not in need. Boyd said he was told of one case of a pharmacist being asked to fill a prescription for 1,000 pills, though the pharmacist rejected the request. He said he heard another case of an out-of-state physician calling in a prescription for four people — a possible indication it was meant for family or friends.

“This new potential use has stirred up the public throughout the country to be trying to get a hold of this, and sadly some physicians have taken the bait,” Boyd said.

Ohio’s pharmacy board met Sunday to impose restrictions on the distribution — limiting new prescriptions to 14 days and requiring positive coronavirus tests. Several other states have taken similar steps. Herdman, Columbus U.S. Attorney David DeVillers and Ohio Attorney General David Yost then issued a statement Tuesday putting doctors on notice that they would investigate those who abused their authority.

“Be assured that we will do our due diligence in holding accountable anyone who may be prescribing outside a legitimate medical purpose,” the statement said. “Where we find doctors or others who are abusing their professional licenses to help themselves or associates, we will move swiftly to identify and prosecute any wrongdoing that is a violation of federal or state law.”

The shortage has real implications not just for those diagnosed with the coronavirus, because those suffering from lupus or other conditions that the drugs treat might not be able to get their medication. Experts say hoarding or misusing them could have severe health consequences.

Boyd said a toddler who ingests even one tablet can die. A Maricopa County, Ariz., couple who had heard about chloroquine on TV and recognized the name on a bottle of chemicals they used to clean their koi pond poured the cleaner into soda and drank it, NBC News reported. The man died, and his wife is in critical condition.

“The stewardship of these drugs, making sure they’re being appropriately prescribed and used, is very important right now,” said Michael Ganio, the director of pharmacy practice and quality at the American Society of Health-System Pharmacists.

Herdman said law enforcement members are still trying to determine the hoarding’s scope and brainstorming creative ways they might charge wrongdoers. He said they have contemplated using the Food, Drug and Cosmetic Act, though they realize there could be hurdles because chloroquine and hydroxychloroquine are not controlled substances that are tightly regulated. He said investigators will look carefully for cases in which physicians gave a false diagnosis or included false information to get a prescription dispensed.

“It’s an aggressive approach, but we think it’s something that we need to pursue, and there are plenty of other theories that should work,” Herdman said. “The great irony here is that we’re all relying on doctors to get us through this, and you turn around, and you’ve got doctors who are just seeking to help themselves out or their loved ones, or maybe in some cases to just purely profit off it, and that’s outrageous.”

Pharmacists, meanwhile, are hopeful that the shortage might abate even without law enforcement intervention. Erin Fox, senior director of drug information at University of Utah Health, said four companies have supplies and while another four have back orders, they are hoping to have more medication by the end of March.

“It sounds like commercial manufacturers are ready to ramp up supplies really quickly,” Fox said. “I’m hopeful that it won’t be a long-term issue.”