1. The prosecution's case collapsed when a material witness failed to appear in court.

2. A material witness failed to appear in court.

3. Al-Kidd was held as a material witness under a federal law adopted after the 9/11 attacks.

4. An FBI agent looks to track down a material witness who is involved in a top-secret investigation.

5. An FBI agent looks to track down a material witness who is involved in...

6. At best, you're material witness to a homicide; at worst, you could be a suspect.

7. As the last person to see her alive, he was a material witness in the case.