Israeli police on Thursday took testimony from US billionaire Sheldon Adelson as part of an ongoing corruption investigation into Prime Minister Benjamin Netanyahu.

The casino mogul arrived at the police Lahav 433 serious crimes unit in Lod to speak with officers about the case. His wife, Miriam, is also expected to be interviewed by investigators.

In leaked audio recordings from 2014, Netanyahu appeared to promise to advance legislation or other measures designed to hobble Adelson’s free Israel Hayom daily newspaper in exchange for more favorable coverage from the competing paper Yedioth Ahronoth.

Adelson and his wife, who are considered close friends of Netanyahu, both agreed to speak to police after being told they were not suspects in the investigation.

Investigators were expected to ask Sheldon Adelson whether he was aware of the alleged quid pro quo deal that the prime minister can be heard discussing with Yedioth publisher Arnon Mozes in the recordings. Netanyahu denies any wrongdoing in the affair, known as Case 2000, and legislation to curtail the free daily was not advanced.

In the recordings, Netanyahu and Mozes reportedly referred to Adelson as “the gingy [redhead].”

Police have wanted to question the Las Vegas casino magnate for some time in connection with the probe. Investigators reportedly reached out to Adelson prior to a visit that was timed to coincide with US President Donald Trump’s stay to Israel on Monday and Tuesday this week. The Adelsons reportedly extended their stay for a few days after the US president left in order to speak to police.

Adelson attended the final speeches Netanyahu and Trump gave at the Israel Museum in Jerusalem on Tuesday just before the US leader left the country.

In another investigation into the prime minister, known as Case 1000, police are probing expensive gifts allegedly given to Netanyahu and his family by wealthy businessmen including US-Israeli movie mogul Arnon Milchan and Australian billionaire James Packer, and whether any actions subsequently taken on their behalf amounted to graft or conflicts of interest. The gifts were reportedly valued at hundreds of thousands of dollars and included expensive cigars, champagne, meals and hotel rooms.

Netanyahu has repeatedly denied any wrongdoing in the cases, insisting that “there will be nothing [found] because there was nothing.”

Times of Israel staff contributed to this report.