Mayor Sid Leiken (pictured) claims he paid his mother’s firm P&G Marketing and Research $2,000 to interview Springfield residents over a proposed new gas tax, which set off an investigation by the Oregon Secretary of State into campaign finance violations because the company was not properly registered.

The mayor, who has repaid the cash, said that he did not document an expenditure transaction correctly but state investigators are now questioning whether the poll was ever actually carried out after corresponding with his mother.

In a letter to Glenda Leiken, Oregon state compliance specialist Kathy Schamp said: “After reviewing your response, we have determined that the information provided does not substantiate that the poll was conducted.”

The state has asked her to provide information about when the poll was created, who drafted it and how it was decided whom to poll. Glenda Leiken must also provide worksheets or phone records for the phone calls and information about anyone who assisted her in the project.

P&G Marketing and Research said that it had made 268 calls to interview 200 people, but pollsters interviewed by the local press last month cast doubts about the unusually high response rate.

Glenda Leiken has until 2 October to provide the state with the information.