1.   A law enforcement official said Tuesday night that FBI agents wanted to test each piece of baggage retrieved from the area for bomb residue.

2.   A test vehicle is sent in with bomb residue purposefully placed in it.

3.   Complicating the search for bomb residue is the simple fact that bombs deployed by terrorists in recent years have contained only small amounts of explosives.

4.   Investigators have closely scrutinized the burned portions of the right wing and have tested it for bomb residue.

5.   Initial tests for bomb residue point to the right wing.

6.   Investigators said on Thursday that they still had not recovered any wreckage that had clearly tested positive for bomb residue.

7.   Other investigators are subjecting some pieces of the wreckage to sophisticated tests, in a search for bomb residue.

8.   They also collected damaged fragments of the actual homes to test for bomb residue.

9.   Prosecutors say clothing inside tested positive for bomb residue.

10.   Other witnesses are expected to testify that shoddy laboratory work meant that bomb residue from other investigations contaminated the Oklahoma City bomb evidence, Newsweek reported.