science

Parallel construction

Parallel construction is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Parallel construction rather than just read about it. In short: Parallel construction is a law enforcement process of building a parallel, or separate, evidentiary basis for a criminal investigation in order to limit disclosure as to the origins of an investigation. In the US, a particular form is evidence laundering, where one police officer obtains evidence via means that are in violation of the Fourth Amendment's protection against unreasonable searches and seizures, and then…

Key takeaways

Parallel construction belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Parallel construction to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Parallel construction from memory before moving on to harder problems.

Reference excerpt

Parallel construction is a law enforcement process of building a parallel, or separate, evidentiary basis for a criminal investigation in order to limit disclosure as to the origins of an investigation. In the US, a particular form is evidence laundering, where one police officer obtains evidence via means that are in violation of the Fourth Amendment's protection against unreasonable searches and seizures, and then passes it on to another officer, who builds on it and gets it accepted by the court under the good-faith exception as applied to the second officer. This practice gained support after the Supreme Court's 2009 Herring v. United States decision.

By the United States Drug Enforcement Administration

In August 2013, a report by Reuters revealed that the Special Operations Division (SOD) of the U.S. Drug Enforcement Administration advises DEA agents to practice parallel construction when creating criminal cases against Americans that are based on NSA warrantless surveillance. The use of illegally obtained evidence is generally inadmissible under the fruit of the poisonous tree doctrine. Two senior DEA officials explained that the reason parallel construction is used is to protect sources (such as undercover agents or informants) or methods in an investigation. One DEA official had told Reuters: "Parallel construction is a law enforcement technique we use every day. It's decades old, a bedrock concept." An example from one official about how parallel construction tips work is being told by Special Operations Division that: "Be at a certain truck stop at a certain time and look for a certain vehicle." DEA would alert state troopers and they may wait for that certain vehicle and use drug searching dogs to identify illegal drug-related activity, giving the appearance the search was conducted randomly. Parallel construction allows the prosecution building the drug case to hide the source of where the information came from to protect confidential informants or undercover agents who may be involved with the illegal drug operation from endangering their lives. A number of former federal agents had used parallel construction during their careers, according to Reuters interviews. Most of the former agents had defended the practice of parallel construction because, according to them, no falsified evidence or illegally obtained material were presented in courts. A judge can rule evidentiary material inadmissible if it is suspected that the evidence was obtained illegally. Parallel construction in this case in the US usually is the result of tips from the DEA, as well as the Special Operations Division that are derived from sources within foreign governments, intelligence agencies or court-authorized domestic phone recordings. According to a senior law enforcement official and a former US military intelligence official tips are not given to the DEA until citizenship is verified to avoid any illegal wiretapping of US citizens who are abroad. US authorities require a warrant to wiretap domestic US-persons (citizens and non-citizens alike) and to wiretap US citizens who are abroad. The Reuters piece occurred amid reporting of the 2013 NSA leaks, although it made no "explicit connection" to the Snowden leaks.

In the United Kingdom The Register argues the Investigatory Powers Act 2016 introduces parallel construction for evidence obtained through surveillance under the act, and prevents it being revealed or questioned in court.

In World War II Parallel construction was used to hide the fact that the Enigma machine encryption had been cracked. Operations based on intelligence recovered this way were authorized if there was a plausible alternate means for the data to have been obtained. Many losses were suffered when preventing them would have alerted the Nazis that Enigma had been deciphered.

In popular culture In Season 5 of The Wire, the Major Crimes Unit, and in particular Lester Freamon, employ an illegal wiretap funded by proceeds diverted from another police investigation in order to dismantle the Stanfield drug organization. The detectives then construct probable cause for the Stanfield arrest warrants, the discovery of which allows Maurice Levy to negotiate Marlo Stanfield's freedom as well as his own.

See also Exclusionary rule Fourth Amendment to the United States Constitution Franks v. Delaware Money laundering

References

Further reading US: Secret Evidence Erodes Fair Trial Rights by Human Rights Watch (January 9, 2018)

Worked examples

Example 1 — a first encounter with Parallel construction

Start with the simplest possible case. Write down what Parallel construction claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Parallel construction before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Parallel construction ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Parallel construction

In research: Parallel construction appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Parallel construction in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Parallel construction is common in secondary-school and first-year university syllabi. It links to neighbouring topics Abuse of the legal system, Evidence law, Injustice, so understanding it makes those chapters shorter.
In everyday life: Look for Parallel construction outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Parallel construction in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Parallel construction means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Parallel construction out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Parallel construction in simple terms?

Why does Parallel construction matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Parallel construction?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Parallel construction.