SAN ANTONIO (AP) — San Antonio police are unveiling several changes to improve the department's investigative process nearly three months after firing a detective who botched more than 130 cases.

Police Chief William McManus spoke about the changes to the City Council's public safety subcommittee on Tuesday, the Express-News reported .

The new procedures make sure only supervisors can close a case in the department's case management system. The changes also aim to improve communication with victims about the investigative process.

"These revisions make them some of the strongest (standard operating procedures) I've ever seen," said Bob Stewart, a law enforcement expert hired by the city to review the changes.

The changes come after Kenneth Valdez, a detective within the Special Victims Unit, was terminated in November for failing to act on DNA evidence, not properly handling evidence and closing cases without supervisor approval. Valdez botched more than 130 sexual assault and family violence case, according to the department. He is appealing the firing.

After Valdez's termination, the department announced it would conduct an internal review of the Special Victims Unit. McManus said the procedures were already solid, but there were some loopholes that allowed investigators to close cases without supervisor approval.

The department ended up reviewing procedures within all seen investigative units to ensure there weren't any additional loopholes. The review process included input from Stewart, several officers, two professors from the University of Texas-San Antonio and six community members.

McManus said he's "very confident" in the new procedures.

The city attorney's office has also begun an external audit of the Special Victims Unit. That review is expected to be completed sometime next month.

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Information from: San Antonio Express-News, http://www.mysanantonio.com