Embattled British Prime Minister Boris Johnson is facing a possible probe into his ties with a US businesswoman.

London authorities asked that the country’s police watchdog look into allegations that Jennifer Arcuri and her tech company, Hacker House, got favorable treatment as a result of her friendship with Johnson while he served as mayor of London, NBC News reported Saturday.

“These are the ingredients of the offence of misconduct in a public office,” said the Greater London Authority’s monitoring office, which oversees the conduct of the city’s government officials and is led by current Mayor Sadiq Khan.

The accusations suggest “a failure to safeguard the public purse and if so that amounts to a significant breach of public trust,” the referral said.

“The Prime Minister as Mayor of London did a huge amount of work when selling our capital city around the world, beating the drum for London and the UK,” Johnson’s spokesperson said in response. “Everything was done with propriety and in the normal way.”

Hacker House is separately under investigation for receiving a grant worth about $130,000 intended for a British-operated business, even though Arcuri had relocated from California less than a year earlier, the Guardian reported.

Johnson’s supporters denounce the referral as a politically motivated attack launched just before his ruling Conservative Party’s annual conference. Khan is a member of the opposition Labour Party.

The allegations were first raised by the British newspaper The Sunday Times.

Arcuri told The Sunday Times: “Any grants received by my companies and any trade mission I joined were purely in respect of my role as a legitimate businesswoman.”

The newspaper added that she did not comment on the nature of her relationship with Johnson, which reportedly included frequent lunchtime “technology lessons” at her apartment.

Arcuri is an entrepreneur, according to her LinkedIn, and founded the technology companies Innotech Network and Hacker House in the UK. Her work in the US ranged from being a radio DJ for the Walt Disney Company to operating a sushi bar in Morro Bay, California.

The scrutiny comes as Johnson attempts to lead the British exit from the European Union, and after the nation’s Supreme Court said his suspension of Parliament was illegal.