BOSTON >> The man who accused Kevin Spacey of groping him at a Massachusetts resort island bar in 2016 asserted his Fifth Amendment right against self-incrimination and refused to testify today after being questioned about text messages the defense claims were deleted.

The man’s decision not to testify caused the judge to question the viability of the case against the two-time Oscar winner, whose career collapsed in 2017 amid a string of sexual misconduct allegations.

Spacey’s accuser was ordered to take the stand after he said he lost a cellphone sought by the defense, which says the man deleted messages that support Spacey’s claims of innocence and provided investigators with manipulated screenshots of conversations.

The accuser, speaking publicly for the first time, said he gave police what he had “available” to him “at the time” and did not alter any of the messages.

“I have no knowledge of any deletions of messages on my phone,” the man said.

The Associated Press does not typically name people who say they are the victims of sexual assault unless they identify themselves publicly. Spacey pleaded not guilty to indecent assault and battery in January.

After being pressed by Spacey’s lawyer about whether he knew that altering evidence used in a prosecution is a crime, the man invoked his right against self-incrimination, and the judge said his testimony today would be stricken from the record.

Spacey’s lawyer urged the judge to dismiss the case, calling it “completely compromised.”

The judge said he would not immediately dismiss the case, but acknowledged prosecutors would have a tough time bringing it to trial if the man won’t testify.

“Once exercised, it may be pretty hard to get around this privilege at trial,” Judge Thomas Barrett said. “The matter may well be dismissed for the reasons indicated,” he said.

The man’s cellphone has been a key issue in the case against Spacey, who is accused of groping the then 18-year-old at a popular Nantucket bar and restaurant, where the man worked as a busboy. The allegations were first made in 2017 by the man’s mother, former Boston TV anchor Heather Unruh.

The accuser’s lawyer, Mitchell Garabedian, said they cannot find the phone, but were able to retrieve a copy of its contents that had been backed up to a computer.

But Spacey’s lawyer said that’s not enough.

“None of that answers the central question, which is: Where is the actual phone? That’s what we want. That’s what we’re entitled to, and we still don’t have it,” Attorney Alan Jackson said.

Unruh told investigators that she deleted items concerning her son’s “frat boy activities” from the phone before giving it to authorities. She acknowledged today deleting things that “concerned” her but denied touching text messages or anything else relevant to the case.

Spacey was not required to attend today’s hearing, and he did not appear.

The accuser’s testimony came days after he voluntarily dismissed a lawsuit that he had filed against the actor about a week earlier.

There was no settlement, Unruh said today. The man’s lawyer said the case was dropped because the accuser is on an “emotional rollercoaster” and wants to focus on the criminal matter.

“He only wanted one roller coaster ride at a time. The criminal case is enough,” Garabedian said.

The man told police he went over to talk to Spacey after his shift ended at Nantucket’s Club Car bar because he wanted to get a picture with the actor. He said Spacey bought him several drinks and tried to persuade him to come home with him before unzipping the man’s pants and groping him for about three minutes.

The accuser told police he tried to move Spacey’s hands, but the groping continued, and he didn’t know what to do because he didn’t want to get in trouble for drinking because he was underage. The man said he fled when Spacey went to the bathroom.

Spacey’s lawyer indicated that the defense would file a written motion to dismiss the case in the coming days. The judge set another hearing for July 31.