A newly declassified CIA document suggests members of the US agency did help to shape the narrative of Zero Dark Thirty, Kathryn Bigelow's recent film about the hunt for Osama bin Laden.

In January the US Senate intelligence committee launched an investigation into whether Bigelow and screenwriter Mark Boal were granted "inappropriate access" to classified CIA material following concern from high-profile members over the film's depiction of torture in the search for the al-Qaida chief. The probe was dropped in February after Zero Dark Thirty, which had initially been tipped as an Oscars frontrunner, left the world's most famous film ceremony with just a single award for sound editing.

However according to Gawker it has now emerged that the CIA did successfully pressure Boal to remove certain scenes from the Zero Dark Thirty script, some of which might have cast the agency in a negative light. Details emerged in a memo released under a US Freedom of Information Act request. It summarises five conference calls held in late 2011 for staff in the agency's Office of Public Affairs "to help promote an appropriate portrayal of the agency and the Bin Laden operation".

Several elements of the draft screenplay for Zero Dark Thirty were changed for the final film upon agency request, according to the memo. Jessica Chastain's Maya, the film's main protagonist, was originally seen participating in an early water-boarding torture scene, but in the final film she is only an observer. A scene in which a dog is used to interrogate a suspect was also excised from the shooting script. Finally a segue in which agents party on a rooftop in Islamabad, drinking and shooting off an AK47 in celebration, was also removed upon CIA insistence. This was agreed to despite the documented use of aggressive dogs in US interrogations of terror suspects at Guantánamo Bay in the early days of George W Bush's war on terror, and despite some of the photographs from the later Abu Ghraib scandal featuring dogs menacing naked prisoners.

The memo appears to confirm suspicions of a cosy relationship between the CIA and Boal, with the agency confident it would be portrayed positively due to the level of help it had provided to the film-makers. "As an agency, we've been pretty forward-leaning with Boal," a CIA staff member wrote to colleagues in documents released last year. "He's agreed to share scripts and details about the movie with us so we're absolutely comfortable with what he will be showing."

In an emailed response to Gawker's piece, Boal denied allowing the CIA to influence creative film-making decisions on Zero Dark Thirty. "We honoured certain requests to keep operational details and the identity of the participants confidential," he wrote. "But as with any publication or work of art, the final decisions as to the content were made by the film-makers."