In a criminal case an appeal by the United States shall lie to a court of appeals from a decision, judgment, or order of a district court dismissing an indictment or information or granting a new trial after verdict or judgment, as to any one or more counts, or any part thereof, except that no appeal shall lie where the double jeopardy clause of the United States Constitution prohibits further prosecution.

An appeal by the United States shall lie to a court of appeals from a decision or order of a district court suppressing or excluding evidence or requiring the return of seized property in a criminal proceeding, not made after the defendant has been put in jeopardy and before the verdict or finding on an indictment or information, if the United States attorney certifies to the district court that the appeal is not taken for purpose of delay and that the evidence is a substantial proof of a fact material in the proceeding.

An appeal by the United States shall lie to a court of appeals from a decision or order, entered by a district court of the United States, granting the release of a person charged with or convicted of an offense, or denying a motion for revocation of, or modification of the conditions of, a decision or order granting release.

The appeal in all such cases shall be taken within thirty days after the decision, judgment or order has been rendered and shall be diligently prosecuted.

The provisions of this section shall be liberally construed to effectuate its purposes.