Iran and China hired private investigators to spy on opposition figures living in the United State, the New York Times reported Sunday.

The NYT said that authoritarian regimes like the Islamic Republic and China increasingly hire detectives to “surveil, harass, threaten and even repatriate dissidents living legally in the U.S.”

Law enforcement officers have told the Times that during the past two years several complaints have been filed in which private investigators, “mostly unwittingly,” were involved in such schemes in different states.

In one case, the New York-based investigator Michael McKeever,71, received a request on his website to track down a debtor who had fled from Dubai to Brooklyn. However, when McKeever started his task by surveilling a house and taking photos of the people coming and going, the FBI warned him that his clients are “bad people and are up to no good.”

At this point McKeever realized he had been used by the intelligence agents of the Iranian regime to kidnap Masih Alinejad, a well-known Iranian-American activist who has been criticizing Iran’s human rights abuses.

“We were afraid they were going to look to snatch and grab her, bring her home and probably kill her,” said James E. Dennehy, the former head of the FBI’s counterintelligence and cyber division in New York, who now runs the bureau’s Newark office.

The report also reveals some other cases in which PIs unwittingly were used by Chinese agents to set up espionage networks, often focusing on national security targets or on individual dissidents.