CNN  — 

House Intelligence Chairman Adam Schiff said on Tuesday night that his committee is still looking into the identity of the person who Rudy Giuliani was speaking with and had the obscured phone number of “-1” – and whether that person is President Donald Trump.

“We can’t confirm yet who” the number belongs to, Schiff said during an interview on CNN’s “Anderson Cooper 360.”

“We are certainly investigating that,” Schiff said. “Rudy Giuliani only had one client – and that was Donald Trump.”

The committee’s impeachment inquiry report shows Giuliani speaking a number of times with that individual during several key moments detailed in the document.

Schiff noted in the interview that the phone number -1 also came up during the trial of former Trump adviser Roger Stone.

According to evidence shown to the jury during the trial, Stone received an incoming call on August 1, 2016, from a phone number listed as -1. That call came roughly six minutes after he had gotten off the phone with then-candidate Trump on a day when he also spoke with Rick Gates, then a campaign adviser to Trump. The evidence at trial did not definitively establish that the -1 calls were coming from any one person, including Trump.

The phone number was listed in phone records released by Democrats as a part of the House Intelligence Committee’s impeachment inquiry report, released Tuesday, but the report does not establish who the number belongs to.

The phone records, which are labeled in the report’s endnotes as coming from AT&T, show a web of communications between journalist John Solomon, Giuliani, Ukrainian American businessman Lev Parnas, House Intelligence Committee ranking member Devin Nunes of California and the White House’s budget office. CNN is owned by AT&T.

Many of the calls occurred in April, according to the Democratic report, the same time Solomon pumped out columns in The Hill. The stories were filled with discredited conspiracy theories about then-US Ambassador to Ukraine Marie Yovanovitch and former Vice President Joe Biden, whose son was on the board of a prominent Ukrainian energy company.