There are laws on the books to penalize police officers who submit false evidence to the court. This includes a New York law passed in 2013 that makes it a crime for officers of the law to make false claims in court, which occur when the officer is aware of the truth and willingly submits a different story.
False evidence takes many forms.
Forged evidence refers to any evidence an officer makes up or alters. For example, an officer can claim the arrested individual behaved in a certain manner at the time of the arrest, which calls for a more serious penalty.
To search a property and acquire evidence, police officers first need to acquire a search warrant. However, some cops will bypass this step and search a property without a warrant and without the owner's consent. Tainted evidence refers to anything submitted through these means. It is not admissible in court, but the officer may claim the individual consented to the search beforehand.
Some officers will attempt to strengthen their case directly at the scene by planting evidence. For instance, the cop may plant a knife, gun or another weapon to make it appear as though the individual was more of a threat. It can also refer to planting saliva, blood or other types of DNA at a scene.
Parallel construction refers to the practice of police officers building a separate case based on other evidence to conceal how a criminal investigation into one person actually came about. As an example, the cops may have illegally acquired evidence on a person for a crime. The cops know they cannot arrest the person now because the evidence they have would be inadmissible in court. Instead, they build another case on supplementary evidence.