A New York City regulator is probing 13 buildings controlled by a company formerly run by Jared Kushner, a top aide to U.S. President Donald Trump and his son-in-law, over possible “illegal activity” related to work permits, according to public filings.

The online filings by the Department of Buildings show that it is investigating the possibility of “false filing” on applications by developer Kushner Companies for construction work. The filings are dated Wednesday and involve properties in the Brooklyn and Manhattan boroughs of New York.

News of the agency’s probe comes two days after a tenants’ rights group and city councilman announced that they had found evidence that Kushner Companies had falsified more than 80 work permits involving 34 buildings in the city.

The probe was first reported by the Associated Press.

A spokeswoman for Kushner Companies, which was run by Jared Kushner until early last year, did not immediately respond to a request for comment. Earlier this week, she said the company values its tenants, takes its legal and ethical responsibilities seriously and would not intentionally falsify filings.

The tenants rights group, Housing Rights Initiative, has alleged that Kushner Companies failed to disclose the existence of rent-stabilized units in its buildings, thereby skirting tighter oversight during renovations and harass tenants.

The group also accused the company of using construction as a means to disrupt the lives of tenants with rent controls and push them out. The tactics, employed by other landlords, have led to a drop in affordable housing in the city, the group says.

The building department’s investigation was assigned to its marshal’s office, which investigates allegations of unlicensed activity by plumbers and other trades and “develops cases for both civil and criminal prosecution,” according to its website.

Reporting by Nathan Layne in New York; Editing by Bernadette Baum