WASHINGTON — The Pentagon misled Congress with inaccurate and vague information about sexual assault cases that portrayed civilian law enforcement officials as less willing than military commanders to punish sex offenders, an Associated Press investigation found.

Local district attorneys and police forces failed to act against U.S. service members who were subsequently prosecuted in military courts for sex crimes, according to internal government records that summarized the outcomes of dozens of cases. But in a number of cases, the steps taken by civilian authorities were described incorrectly or omitted. Other case descriptions were too imprecise to be verified.

There also is nothing in the records that supports the primary reason the Pentagon told Congress about the cases in the first place: To show top military brass as hard-nosed crime fighters who insisted on taking the cases to trial.

The records were obtained through the Freedom of Information Act by the advocacy group Protect Our Defenders, which provided the documents exclusively to AP. Protect Our Defenders is scheduled to release a report Monday that criticizes the Pentagon’s use of the cases to undermine support for Senate legislation that would mandate a major change in the way the military handles sexual assault allegations.

The bulk of the cases involved soldiers. Army spokeswoman Tatjana Christian said the case descriptions were written by service attorneys who had “personal and direct knowledge of the circumstances.” She said they contacted the local authorities in each case to ensure the description was accurate, although there is no indication of that in the summaries. The Army declined to make a service official available for an interview.

Previously, the more than 90 cases had been discussed publicly only as statistics that underpinned the Pentagon’sobjections to the Senate bill, the Military Justice Improvement Act.

Three years ago, Navy Adm. James Winnefeld, then the vice chairman of the Joint Chiefs of Staff, used the numbersto warn a Senate panel that if approved, the bill would result in fewer sexual assault cases going to trial. Winnefeld retired from military service last year.

In response to the AP’s reporting, Joint Chiefs of Staff spokesman Richard Osial described the information that Winnefeld provided the committee as a snapshot based on data that was supplied by the military services. “He had confidence to go with it,” Osial said.