President Donald Trump's personal lawyer Michael Cohen arrives at his hotel in New York City, June 20, 2018.

Investigators in New York have subpoenaed President Donald Trump's former personal lawyer Michael Cohen as part of a probe of the Trump Foundation.

"A subpoena has been issued to Michael Cohen for relevant information in light of the public disclosures made yesterday," James Gazzale, a spokesperson for the New York State Department of Taxation and Finance, told CNBC on Wednesday.

A source familiar with the investigation told CNBC that anything the Tax Department uncovers through its investigation will be referred to the New York State Attorney General's Office for prosecution.

Cohen pleaded guilty on Tuesday to eight criminal charges, including tax fraud and campaign finance crimes, in New York federal court.

He said that during the 2016 presidential campaign he had unlawfully facilitated payments to two women who have said they had sex with the president. Trump and his lawyers have denied wrongdoing.

Gazzale said his department will work with the Attorney General's office, as well as the Manhattan District Attorney.

Cohen's lawyer, former Clinton White House aide Lanny Davis, has said Trump himself "directed" Cohen "to commit a crime."

Davis has also expressed a willingness for Cohen to cooperate with state and federal prosecutors, including special counsel Robert Mueller, who is investigating Russian meddling in the 2016 presidential election.