From the transcrip
DAVID MUIR: I called the author of the Pew report last night. And he told me that they found no evidence of voter ...
(OVERTALK)
DAVID MUIR: ... fraud.
PRESIDENT TRUMP: Really? Then why did he write the report?
DAVID MUIR: He said no evidence of voter fraud.
PRESIDENT TRUMP: Excuse me, then why did he write the report?
Maybe he wrote the report and concluded there was NO evidence and reported there was no evidence.