The investigation will look into allegations that officers and members at Westminster tried to derail the successful bid by Walterton and Elgin Community Homes to take over council homes under tenants' choice legislation.
Mr Magill has still to give a final view on the level of surcharge in the 'homes for votes' scandal.
'I propose to undertake a further and thorough review of the documentary evidence and . . . may if appropriate, carry out a number of interviews,' said Mr Magill in a letter to WECH.
The report says there was a difference between support for 'residents' choice' as a council policy and a continuation of the 'war' with WECH by council members.
'It appears that senior officers made investigations and provided information to assist the attempted, but unsuccessful, political lobbying and influencing of government and the Housing Corporation, and the attempted derailing of the WECH bid,' says the report.