Moreover, the Supreme Court recently held in Ashcroft v. al-Kidd that "an objectively reasonable arrest and detention of a material witness pursuant to a validly obtained warrant cannot be challenged as unconstitutional on the basis of allegations that the arresting authority had an improper motive." Critics, however, contend that since September 11, 2001, seventy individuals, mostly Muslims, have been arrested and detained in abuse of the statute's authority. Earlier Legislative Activity

		H.R. 3199 (109th Congress)

Witnesses at Congressional oversight hearings charged that the authority under 18 U.S.C. 3199 following the hearings, section 12 of the bill would have amended section 1001 of the USA PATRIOT Act by directing periodic review of the exercise of the authority under section 3144. Perhaps due to Administration opposition, the provision was dropped from H.R. 3199 prior to House passage. No similar provision could be found in H.R. 3199 ( S. 1389 ) as approved in the Senate, in the conference bill, H.Rept. S. 1739 (109th Congress)

S. 1739 , introduced by Senator Leahy, would have rewritten section 3144. In its recast form, section 3144 among other things would:
establish a preference for postponing arrest until after a material witness has been served with a summons or subpoena and failed or refused to appear, unless the court finds by clear and convincing evidence that service is likely to result in flight or otherwise unlikely to secure the witness' attendance; make it clear that the provision applies to grand jury proceedings; explicitly permit arrest by officers who are not in physical possession of the warrant; require an initial judicial appearance without unnecessary delay in the district of the arrest or in an adjacent district if more expedient or if the warrant was issued there and the appearance occurs on the day of arrest; limit detention to 5 day increments for a maximum of 30 days (10 days in the case of grand jury witness); require the Attorney General to file an annual report to the Judiciary Committees on the number of material witness warrants sought, granted and denied within the year; the number of material witnesses arrested who were not deposed or did not appear before judicial proceedings; and the average number of days arrested material witnesses were detained. The 109 th Congress adjourned without further action on these or any other legislative proposal to amend section 3144. No comparable proposals emerged in any subsequent Congress. Citations to State Material Witness Statutes
This is an overview of the law under the federal material witness statute which authorizes the arrest of material witnesses, permits their release under essentially the same bail laws that apply to federal criminal defendants, but favors their release after their depositions have been taken.
Legislative efforts in the 109th Congress to amend the provisions never fully developed. Witnesses at Congressional oversight hearings did alleged that the authority to arrest and hold material witnesses until their appearance at federal criminal proceedings (including grand jury proceedings) had been abused following September 11, 2001. Section 12 of the USA PATRIOT Act and Terrorism Prevention Reauthorization Act (H.R. 3199) as reported by the House Judiciary Committee would have required periodic reviews and reports on the use of the material witness statute. In the face of Administration opposition, however, the provision was dropped from the bill prior to House consideration. No similar proposal could be found in the version of H.R. 3199 (S. 1389) approved in the Senate or in the conference bill sent to the President. S. 1739, as introduced, would have rewritten the federal statute, setting detention time limits and raising evidentiary standards for arrest and detention among other things. The 109th Congress adjourned without further action on the material witness proposals, and subsequent Congresses passed without renewed legislative interest.
The Supreme Court resolved on other grounds a case which might have been used as a vehicle to address constitutional challenges to the statute or use, Ashcroft v. al-Kidd, 131 S.Ct. 2074 (2011). Concurring opinions there, however, suggest that several members of the Court consider the matter an open question.
A list of citations to comparable state statutes is appended.
The report appeared in an earlier version as CRS Report RL33077, Arrest and Detention of Material Witnesses: Federal Law In Brief, by [author name scrubbed].