WASHINGTON  On a September morning in 2002, the police monitoring protests at the I.M.F./World Bank meetings descended on Pershing Park here and arrested, hogtied and confined for hours hundreds of peaceful protesters, innocent bystanders and other people on their way to work.

Those actions led to federal lawsuits that have already cost the city more than a million dollars in legal fees and settlements. They also elicited a sharp reprimand this summer from a federal judge handling one of the cases after it was revealed that city officials lost, destroyed or possibly doctored records relating to the arrests.

In hopes of drawing the matter to a close, city officials last week released an investigative report about the missing documents. But the report, which was produced by Stanley Sporkin, a retired federal judge, called for a further inquiry and raised more questions than it answered.

Charged with explaining the mysterious gaps in audiotapes from the period surrounding the arrests, Judge Sporkin had also sought to investigate the disappearance of the “running résumé,” a detailed log of police activity from the day of the arrests.