Police are deciding whether to investigate a council's decision to approve the building of a huge warehouse next to residential homes.
Planning reviewer Marc Dorfman called the decision to approve the building in Blakelands, Milton Keynes "bona fide".
But he told Milton Keynes Council that Thames Valley Police would use his report to decide if an inquiry was "warranted".
The police said any probe would look at conduct of council officials.
The 20,522-sq-metre (24,544-sq-yd), 18m-high (59ft) warehouse on Yeomans Drive was granted planning permission in 2017, when Labour was in charge of the council.
Residents, who say it overlooks their homes, had expressed concerns about the planning process, in particular the case being reallocated from a planning officer who had recommended permission be refused.
The council, which now has no single party in control but has a Labour leader, commissioned external planning expert Mr Dorfman to write a report in July 2019.
His interim findings, published last month, concluded the planning decision was "bona fide [made in good faith] and proper" and it was "perfectly reasonable" to have reallocated the case.
Reviewing the report on Tuesday, after Mr Dorfman produced further information, the council's audit committee rejected Conservative calls for a full external audit.
It has been decided to wait for Mr Dorfman's final report in January in order to decide the next steps.
Mr Dorfman told the meeting the second planning officer had revealed she "would have liked to have written it up for a refusal" but was "coerced" into approval.
Conservative councillor and vice chair of the development control committee, John Bint, who originally called the review "unfit for purpose", said: "I don't think we're close to answers yet."
Meanwhile, residents have handed a dossier of concerns to Thames Valley Police and Mr Dorfman said the force was now waiting for his final conclusions.
A police spokesman said: "An assessment is being conducted by the Economic Crime Unit to determine if an investigation is warranted.
"This assessment will focus only on any conduct that may constitute a criminal offence and not the specifics of the wider planning issues and decisions."
Pete Marland, the Labour council leader, had said the interim report made it seem "very clear the decision on Blakelands warehouse was legal".
He has been approached for further comment.
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