Far too often, police officers use a pretext such as a broken tail light or some other minor traffic violation to make a stop. Then they try to search the vehicle for drugs or other evidence.
Pretext stops are inherently questionable. And it’s even worse when the dubious stop comes after federal authorities ask state or local law enforcement to conduct a search because of information obtained through constitutionally suspect means.
Is it illegal for police to make stops that result from this type of information-sharing between government agencies?
The secret role of federal agencies
Government agencies contend that stops or arrests resulting from information-exchanges between agencies are generally permissible. But critics are increasingly raising serious concerns about this. They point to the secret role that federal agencies play in providing evidence to local police and prosecutors.
In a recent report, Human Rights Watch documented how federal agencies often make requests to state or local law enforcement agencies to create pretext for stops. The stops are pretexts because the real goal is to use them to search for drugs or other incriminating information. The Drug Enforcement Administration (DEA) is one agency prone to using such tactics.
Law enforcement agencies call this type of collaboration “parallel construction.” It allows police and prosecutors to come up with alternative explanations for how they got the original evidence that led to stop or search — and then use these “parallel” stories to conceal the real underlying source.
This makes it much more difficult for defendants to challenge government misconduct.
Fruit of the poisonous tree
A key problem with this is that the information the DEA or another federal agency provided to state or local law enforcement may have come from constitutionally impermissible sources. These sources can include warrantless searchesphone surveillance or unreliable informants.
If evidence was illegally obtained, under the Constitution it may not be used against a defendant. The legal term for this is the “fruit of the poisonous tree.” A long line of cases uphold this principle.
To be sure, the government can try to get around the poisonous tree problem by showing that the information it acted upon came from an independent source or would inevitably have been discovered.
But defense attorneys and other advocates for constitutional rights are pushing back strongly against government tactics that conceal the source of information used by criminal investigations.
In one recent case, a federal appeals court required local enforcement agencies to make greater disclosure of their use of surveillance technology. The case was brought under the Freedom of Information Act and involved the tracking of suspects’ locations.
Putting a stop to dubious stops
Under the Constitution, the general rule is that police are not supposed to stop a vehicle unless there is probable cause to believe an offense has been committed.
If you have been charged with a criminal offense following a traffic stop, it is important for you to contact an experienced attorney who can determine if the stop was pretextual and if there is a constitutional challenge that should be made.