LAS VEGAS >> David Copperfield testified today that he didn’t know until he was sued that a British tourist claimed to have been seriously injured while taking part in an illusion during a performance on the Las Vegas Strip in 2013.

Although Copperfield said it might be his fault if an audience volunteer who was participating in an illusion got hurt, the celebrated magician didn’t acknowledge responsibility for injuries Gavin Cox claims to have suffered when he fell.

“It depends on what happened. If I did something wrong, it would be my fault,” Copperfield said during questioning by Cox’s lawyer, Benedict Morelli.

“Your defense in this case is … if they participate and someone gets hurt, it’s their fault, not yours. Is that accurate?” Morelli asked. “Yes or no?”

“It’s not a simple yes-or-no answer,” Copperfield responded in a barely audible voice.

Morelli contends that before Cox fell, the group of audience volunteers participating in the illusion was hustled through an alley coated with what he called construction dust. The people were taking part in a signature illusion that appeared to make them vanish onstage and appear a few moments later in the back of the theater.

Copperfield said he didn’t know whether there as a powdery residue near a trash bin in an MGM Grand alley. He said he passed through the same outdoor alley alone while performing another illusion about 10 minutes earlier, and didn’t notice any debris.

“If in fact there was construction dust, could that be your fault if someone fell and got hurt?” Morelli asked.

Copperfield responded that he couldn’t answer a hypothetical question before proceedings ended for the day.

The 61-year-old performer is due to return to the witness stand next Tuesday for more testimony in Clark County District Court.

Cox, a resident of Kent, England, claims lasting brain and body injuries and more than $400,000 in medical expenses. He and his wife, Minh-Hahn Cox, are seeking unspecified damages in their lawsuit, which also names as defendants the MGM Grand, show producer Backstage Employment and Referral, and construction firm Team Construction Management.

Copperfield’s lawyers lost pretrial bids to close proceedings to the public to avoid disclosing performance secrets, although Judge Mark Denton has said some portions of Copperfield’s testimony might still be conducted behind closed doors.