The person told The Associated Press on Saturday that investigators aren't sure of the significance of the names and don't know if it was a list of people he was targeting.
Congressman Steve Scalise has improved following another round of surgeries and is speaking with loved ones, hospital officials said Saturday.
For now, Scalise remains in critical condition in the hospital's intensive care unit.
The rifle-wielding 66-year-old, who died during the attack, had a history of anger aimed at Republican officials.
Hospital officials said it is hard to predict how long the congressman will be in the hospital, but that he is expected to be able to walk and hopefully run after a period of rehabilitation.
According to Sava, several operations have controlled the bleeding and Scalise's vital signs have stabilized.
Trump said Friday his "dear friend", Scalise, "took a bullet for all of us".
The shooter, James T. Hodgkinson, was killed by police Wednesday after firing dozens of bullets during the congressional practice session. His risk of death is "substantially lower" than it was when he was admitted to the hospital on Wednesday, and "I think that an excellent recovery is a good possibility", Sava said.
Scalise was fielding ground balls at second base Wednesday when he was shot at a practice for the annual Republicans-Democrats baseball game.
Sava said that Scalise (R-La.) has largely been sedated, but able to notice the presence of his family and the medical staff when doctors lessened his sedation.
Also suffering relatively minor injuries were two Capitol Police officers, David Bailey and Crystal Griner, and House GOP aide Zack Barth.
Scalise will require additional operations, Sava said, adding that it's hard to predict how long he will be in the hospital.
One of the injured officers, Krystal Griner, is still being treated at the MedStar Washington Hospital Center after being shot in the ankle.