Denver Auditor Dennis Gallagher on Tuesday fired off a letter accusing the sheriff’s department of obstructing an audit of the embattled agency.

“Frankly we have encountered recalcitrance, foot-dragging and what I can only describe as obstructionist behavior on the part of some members of the Sheriff’s Department as we have tried to conduct our audit. This kind of behavior and the refusal to provide needed information to my auditors makes me wonder what some people want to hide,” said the letter addressed to Mayor Michael Hancock.

Gallagher asked the mayor to instruct the sheriff’s department to cooperate with the auditors.

Gallagher sent the letter after officials in the sheriff’s internal affairs bureau refused to release data for a trend analysis of complaints from inmates, said Denis Berckefeldt, a spokesman for the auditor.

The auditors were not asking for names and other information that would identify specific cases, he said.

Throughout the audit, the department has been slow to respond to requests for information, Berckefeldt said.

“These are delaying tactics, and we just thought this is the final straw,” he said.

Gallagher opened his investigation in October and planned to have it completed by March. Previously, he said the audit would focus on the department’s disciplinary process.

The audit is one of multiple reviews of the sheriff’s department’s operations. All of the reviews are the result of multiple excessive-force cases inside the two jails, including two that resulted in legal payouts totaling nearly $10 million.

“We take the Auditor’s function very seriously and share his office’s commitment to transparency and responsible government,” City Attorney Scott Martinez said in a statement. That’s why we have dedicated considerable time and energy to gathering the large amount of information the Auditor’s Office has requested.

“However, there are often legitimate legal reasons that prevent records from being provided to the Auditor’s Office. As with any disagreement between the Auditor’s Office and a city department, my office will be reviewing these specific documents and making a legal determination on whether they can and must be disclosed.”

Noelle Phillips: 303-954-1661, nphillips@denverpost.com or twitter.com/Noelle_Phillips