You should first think about the difference between reports and evidence. Any person's written statement, for example, is potentially a piece of evidence. A defendant's confession would certainly fall in that category. Separate laws deal with how long a police department must retain evidence. Retention laws deal with reports.
There is a section in the TX Govt Code that deals with records retention policies that you should maybe look at. Also, contact the Texas State Library for help.
Records Management Assistance for Local Governments State and Local Records Management serves almost 9,000 Texas local governments by providing training and consulting services in all aspects of records and information management.
