Iowa Code § 719.3: Preventing apprehension, obstructing prosecution, or obstructing defense.

A person who, with intent to prevent the apprehension or obstruct the prosecution or defense of any person, knowingly does any of the following acts, commits an aggravated misdemeanor:

1. Destroys, alters, conceals or disguises physical evidence which would be admissible in the trial of another for a public offense, or makes available false evidence or furnishes false information with the intent that it be used in the trial of that case.

2. Induces a witness having knowledge material to the subject at issue to leave the state or hide, or to fail to appear when subpoenaed.