An audit of selected operations in the city Parking Department reveals that one company is receiving nearly 90 percent of the city’s private towing business.

The city comptroller’s report shows that from January 2011 through March 2012, Riverside Towing and Recovery had 89 percent of city business among private contractors, or $89,810, while two other contractors, Jim Mazz Auto Inc. and South Buffalo Auto Parts, each had about $5,780 in business.

The long-awaited audit was filed with the Common Council this week and had been in the works for about a year. The audit began before Comptroller Mark J.F. Schroeder took office in January, and its completion was delayed by the firing of former city auditor Darryl McPherson, said comptroller spokesman Patrick Curry.

Parking Commissioner Kevin Helfer declined to comment directly on why one company was receiving so much towing business, but he said Mayor Byron W. Brown is aware of the situation and that he would be willing to discuss it with the Council during an executive session.

He also declined to comment on the comptroller’s suggestion that new bids for towing services be sought, based on state procurement law that requires purchases of more than $35,000 to be formally bid. The audit states that current contracts date back to March 2000.

The city changed its towing policy in May after a federal investigation into allegations of bribery and the murder of a tow truck driver.

Under the policy, the city has an authorized list of towing companies, and the companies are rotated weekly. The first tow truck that is called in the case of an accident is from the city’s Police Department, Helfer said.

The audit focused on the department’s towing and storage operations, as well as its auto auction procedures.

It follows a guilty plea from May 2011 in which the superintendent of the city’s fleet operations, John R. Womer, admitted skimming money from the city’s impounded car auctions.

Womer, who resigned from the city, paid $8,575 in restitution. He was caught after Helfer started at the department and instituted better internal controls, Helfer said.

An earlier version of the audit noted that since the arrest of two employees accused of stealing quarters from parking meters, meter revenue has increased 38 percent.

Helfer said that though the revenue increase was good news, it wasn’t relevant to the audit, because the comptroller’s investigation concerned towing and storage, not parking meter operations.

The audit credits Helfer’s leadership and better advertising with the growth in revenue – 77 percent from 2009 to March 2012 – from the city’s auction of impounded cars.

The audit also suggested changes to the city’s impound lot, including computerization of inventory, but Helfer said a manual count is more effective.