New York (CNN) President Donald Trump's former personal attorney, Michael Cohen, sued the Trump Organization on Thursday, saying that after Cohen began cooperating with federal investigators, the company failed to fulfill its contractual obligations to indemnify him or pay his legal bills relating to his work for the firm.

Cohen -- an executive at the Trump Organization until early 2017, when he left that post to work as Trump's personal attorney -- alleged in the lawsuit the company is obligated to pay both his legal bills, which now total at least $1.9 million, and another $1.9 million he owes as part of a criminal sentence he received late last year.

Cohen incurred legal bills from several law firms starting in 2017, when he began to face multiple inquiries, including congressional hearings, civil lawsuits, the investigation from special counsel Robert Mueller and, by 2018, a criminal probe from the Manhattan US Attorney's office.

In July 2017, according to the lawsuit filed in the New York state Supreme Court, the Trump Organization agreed to indemnify Cohen and to pay his attorneys' fees and costs in connection with related investigations.

"The Trump Organization and Mr. Cohen were proceeding pursuant to a 'joint defense' at that time with respect to the Investigations and other matters," the lawsuit says.

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