A timeshare is a vacation home in which multiple people share ownership. They purchase blocks of time at the property every year in what is usually a long-term or even lifetime commitment.

“Timeshare fraudsters aim to suck their victims dry, with devastating consequences to victims’ financial futures, relationships, and physical and emotional health,” Assistant Special Agent in Charge Paul Roberts, head of FBI New York’s Complex Financial Crimes Branch, said in a statement.

“As the cartels further cement their control of this space, it’s especially critical that the FBI take the lead in addressing this threat to American seniors,” he added.

The FBI says the Jalisco New Generation Cartel is the primary group engaging in timeshare fraud, but others are likely using independent call centers to carry out the fraud too.

The cartels conduct “extensive research on their potential victims” before creating fake documents and reaching out to them through phony email accounts, according to the agency.

“Throughout the process, the fraudsters use a combination of high-pressure sales tactics and cyber-enabled fraud strategies, such as mimicking legitimate entities’ email addresses and forging official documents, to convince victims that each phase of the scam is legitimate,” Roberts said.

Timeshare fraud is often unreported because victims either don’t realize they are being scammed or they become afraid to come forward, the FBI says.

“There is nothing embarrassing about falling victim to a scam like this,” Roberts said. “The worst thing that people can do is suffer in silence out of shame or fear of judgment.”

Roberts says the top signs to watch out for to avoid timeshare scams are never to pay upfront fees and never hand over a power-of-attorney form.

Anyone who contacts you claiming to be a government official should never ask you about a timeshare settlement, threaten to arrest you if you don’t pay, or threaten to subpoena you to court outside the United States, Roberts said.

Recovering money from criminals after it’s lost in an online scam is notoriously difficult. If you are the victim of a financial scam, the Federal Trade Commission recommends reaching out to your bank or whatever credit card or money service you used to try and recover the funds.

The FTC recommends reporting known timeshare scams to its website, the state attorney general where the crime took place, and the Better Business Bureau. You can report timeshare and vacation club scams to the FTC here.