Vice reported that Hadi Matar, 25, was communicating with members of the militia over social media prior to the attack, citing anonymous intelligence sources.
Iranian government officials have denied any involvement in Friday’s attack on Mr Rushdie at the Chautauqua Institution in western New York state and there is no evidence they were involved in planning the attack.
But according to a European intelligence official who spoke to Vice, the stabbing bore all the hallmarks of a “guided attack”.
The official said “close scrutiny” needed to be paid to his online communications as it appeared someone had been instructing Mr Matar on when and how to carry out the attack.
A Middle Eastern intelligence source told Vice that it was obvious that Mr Matar had been in contact with “people either directly involved with or adjacent to” the Revolutionary Guard’s external operations force.
“It’s unclear the extent of the involvement, if this was a directly supported assassination attempt or if it was a series of suggestions and directions in picking a target,” the official told the media company.
Law enforcement sources told NBC News that Mr Matar’s social media accounts appeared to show he had made sympathetic posts about the Revolutionary Guard.
A computer and other electronic devices were confiscated along with knives and a tool for sharpening blades from his home in Fairview, New Jersey, his mother Silvana Fardos told DailyMail.com.
On Sunday, Mr Rushdie’s son Zafar said his father had been taken off a ventilator and was speaking, but remained in a critical condition.
“Though his life changing injuries are severe, his usual feisty and defiant sense of humour remains in tact.”
Mr Matar has been charged with the author’s attempted murder and is being held without bail.
The Revolutionary Guard is a branch of Iran’s armed forces formed in 1979 and states that its role is to protect Iran’s Islamic system of government and resist foreign threats.
It is thought to have up to 250,000 military personnel.