Michael Cohen, the prosecution’s final witness in Donald Trump’s criminal trial, is returning to the stand for a fourth day of testimony Monday, the last appearance he is expected to make.

Cohen is the key witness in the case against Trump as the only person who has testified that Trump had personal knowledge of an alleged scheme to falsify business records to cover up reimbursements for a pre-election “hush money” payment to an adult film star in 2016.

He’s already faced seven hours of withering cross-examination depicting him as a frequent liar who is obsessed with Trump and determined to make money off the cases against him. Trump attorney Todd Blanche said on May 16, the most recent day of proceedings, that he has at least an hour of questions remaining for Cohen.

Prosecutors, who need Cohen’s testimony to seal the case, also have more questions for him.

Last week, Blanche played for the jury clips of Cohen talking about Trump last year on his podcast.

“I truly f–king hope that this man ends up in prison,” Cohen was heard saying in one clip. “You better believe I want this man to go down and rot inside for what he did to my family.”

Cohen has admitted to lying under oath about the $130,000 “hush money” payment to adult film star Stormy Daniels before the 2016 election. Cohen pleaded guilty to federal charges in 2018 stemming from the deal, including bank fraud and campaign finance violations.

Prosecutors allege 34 business records were falsified to cover up that payment, and have shown the jury the invoices, vouchers and checks that correspond to each felony charge Trump faces. The former president has pleaded not guilty.