The person wasn't authorised to discuss the matter publicly and spoke to AP on condition of anonymity.
The Trump-friendly tabloid has a history of trying to help him. An attorney for the head of the National Enquirer's parent company says the tabloid didn't commit extortion or blackmail by threatening to publish Bezos' explicit photos. It's not unusual for him to lash out at The Washington Post owner.
The brother, Michael Sanchez, is a supporter of President Donald Trump and an acquaintance of Trump allies Roger Stone and Carter Page.More news: Shannon Gabriel charged by ICC after Joe Root exchange
Michael Sanchez did not immediately respond to a message seeking comment on Monday.
Napolitano concluded that the actions of David Pecker-CEO of National Inquirer's publisher American Media (AMI)-amounted to "an act of blackmail because it is an effort to prevent [Bezos] from doing what he has a right to do by threat of exposing something".
When Stephanopoulos directly asked Elkan Abramowitz if the National Enquirer source was Michael Sanchez, Abramowitz said he couldn't disclose who the source is because of confidentiality constraints. Sources from inside AMI told The Daily Beast that Michael Sanchez was the source of the texts to the National Enquirer.More news: Michelle Obama’s text exchange with mom is so relatable
The Daily Beast, which has been tracking the story of Bezos' private investigation into the leaked texts, spoke with Bezos' security consultant Gavin de Becker, who said they've wrapped up the leak investigation.
AMI was implicated in one of the charges after they admitted to paying $150,000 to gain exclusive rights to former Playboy model Karen McDougal's story of an alleged affair with Trump-a "catch and kill" agreement-in order to kill her story amid the 2016 presidential campaign. "We have turned our conclusions over to our attorneys for referral to law enforcement", he told the outlet Sunday, but declined giving further details. Ben-Veniste had served as special prosecutor during the Watergate scandal. The company's blowout success made its founder and CEO, Bezos, No. 1 on Forbes' billionaires list this year. AMI said it stands behind its reporting and that it acted "lawfully".More news: Australia refuse to play in Pakistan, series shifted to UAE