Michael Cohen faced a fierce cross-examination on Tuesday afternoon in the criminal trial of Donald Trump, as the defense tried to tear down the prosecution’s key witness.

Mr. Cohen was repeatedly attacked by Mr. Trump’s attorney, Todd Blanche, who suggested he was being evasive on the stand, had selective amnesia and was a jilted former employee profiting off his hatred of the former president.

Mr. Cohen, once Mr. Trump’s personal lawyer, has testified that Mr. Trump directed him to pay $130,000 in hush money to Stormy Daniels, a porn star, to suppress her account of a sexual rendezvous with him in a Lake Tahoe hotel in 2006.

Mr. Trump faces 34 felony counts of falsifying business records to hide the reimbursement of Mr. Cohen. Mr. Trump, 77, has denied the charges and says he did not have sex with Ms. Daniels. If convicted, he could face prison or probation.

Here are five takeaways from Mr. Trump’s 17th day on trial:

We could be near the end, but Trump is a wild card.

Prosecutors indicated Tuesday that Mr. Cohen would be their last witness, and the defense said that it hoped to be done with cross-examination Thursday, the week’s only remaining day of court.

After that, the defense can present its case, though it is not clear how long that might take. On Tuesday, Mr. Trump’s lawyers told the judge, Juan M. Merchan, that they could begin Monday, and that the defendant might testify.