Haringey Council handed control of a business park to a local rapper without any formal agreement in place.
The Ham&High used Freedom of Information laws to ask for a copy of the contract appointing Teriy Keys as tenant-landlord at 141 Station Road, Wood Green.
But the council said it did not exist because the agreement was “undertaken on an informal basis”.
Lib Dem leader Luke Cawley-Harrison has called for “an entirely independent and external investigation” into the "bizarre" arrangement.
In July, the Ham&High revealed Mr Keys was given the site at zero rent, despite other bidders offering to pay.
One of them, woodworker Eugene Lebedenko, asked to see all the proposals but the council refused.
They have also refused to show them to the Ham&High, saying they contain personal and commercially sensitive information.
Lib Dems are now demanding to see them.
Labour councillors have already ordered an internal audit investigation.
In June, the Ham&High published CCTV footage of criminal activity at the site, triggering two police investigations.
Tenant-landlord Mr Keys - stage name, Smurfie Syco - complained that his plan to turn the site into a community hub had been frustrated by trespassers who kept invading the site to commit crimes.
He has since been removed from post by Haringey, which is now planning a prefabricated homeless hostel on the land.
Councillors who asked questions after our initial story identified what they felt were anomalies in the way civil servants had selected the tenant-landlord.
Three existing tenants, including Mr Keys, were invited in 2019 to bid to take over the site for £10,000 per year - but Mr Keys got it for nothing.
The Ham&High asked to see proof of a competitive tender scoring process, but the council said there was "no evidence" of this because a single officer had made an “informal” decision.
A council spokesperson said of the internal audit: "If this throws up evidence or failures that require external audit or inquiry, that is the process we would follow."
They added that Freedom of Information decisions were "made in accordance with the law" and that the council had already tightened its rules around letting and management of properties.
For more, read:
Concerns raised over homeless housing scheme next-door to school
Haringey Council launches investigation into land deal with rapper
Police probe attack, lockdown parties and apparent drug use on council site
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