The Washington Post made an Open Records Request to try to get access to (they wanted to test for DNA) physical evidence from a capital case, post-execution. AG's office repeated what we knew: that's not what the Public Information Act is about. Link to the letter ruling, OR2003-6798:
http://www.oag.state.tx.us/opinopen/opinions/orl50abbott/orl2003/or036798.htm