Arrest, Search, and Warrant

Definitions

Fourth Amendment to the United States Constitution: "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

Arrest. To deprive a person of his liberty by legal authority to answer a civil or a criminal demand. Arrest is accomplished by some act by the officer indicating intention to detain or to take the person into custody and thereby subjecting that person to the control and will of the officer.

Arrest Warrant. A written order issued by the court, that is made on behalf of the state or United States. It is based upon a complaint issued pursuant to statute and/or court rule, and it commands law enforcement officer to arrest a person and bring him before a magistrate.

Search. Looking for or seeking that which is concealed from view.

Search Warrant. A written order issued by a justice or other magistrate, on behalf of the state or United States. It directs an officer, authorizing him to search for and seize any property that constitutes

• evidence of the commission of a crime,
• contraband,
• the fruits of crime,
• things otherwise criminally possessed, or
• property designed or intended for use which is or has been used as the means of committing a crime.

Probable cause is required for arrests, searches, and warrants. In 1983, the United States Supreme Court (Illinois v. Gates) defined the requirements to meet probable cause. Specifically, the decision said

• the totality of the circumstances are to be used,
• probable cause is to be viewed as a set of probabilities, and
• a deficiency in one probability can be compensated by the probability in another.

The requirements expressed by the United States Supreme Court have been implemented for the first time by FactLogic.

FactLogic determines and quantifies the probability of guilt, the accuracy of your decision can be demonstrated, and it can be substantiated by the judgments of others:

Accurate Decision. FactLogic uses your judgments about independent facts and combines them according to the laws of probability. You can now make decisions with an accuracy never before possible.

Substantiated Decision. A definition of probable cause refers to " ... circumstances which would lead a reasonably prudent man to believe in guilt of the arrested party." If you enlist the independent judgments of others, you can develop a more accurate probability of guilt with which to compare to probable cause. If substantiated by others, your decision is easier to defend as being that of a "reasonably prudent man." The accuracy of your decision depends upon the number of independent judgments and their variation; hence, your estimate of the probability of guilt can be as accurately as you choose.

1. One Fact Finder:
Determine the Probability of Guilt

A single fact finder can use FactLogic to determine the probability of guilt and compare it to probable cause. This analysis is possible only because judgments are quantified and FactLogic reduces them to a single number. Consider two examples, one of an arrest and the other of a warrant.

Example (Arrest). Officer Schmidt spotted a speeding car about 50 yards away in which a female passenger seemed to be fighting with the driver. Moreover, the driver was holding a rifle and pointing it out the window. After a brief chase, Officer Schmidt arrested the driver. Determine if the arrest for kidnapping is justified?

Solution (Arrest). The independent facts for this arrest are listed in Table 1. Officer Schmidt entered the probabilities for which FactLogic determines the probability of guilt to be 77.457%, a value that seems to exceed probable cause by a good margin.

Example (Warrant). The case of Illinois v. Gates concerned a search of a house in Bloomingdale, Illinois based upon an anonymous letter that stated drugs were kept in the house. The letter also provided details of a trip by the owners of the house to Florida to purchase drugs. Before searching the house, the police independently verified the details of the drug purchase in Florida. An Illinois state-court judge issued the search warrant for the house. Determine if the evidence met probable cause to search the house.

Solution (Warrant). Reasonable probabilities are entered for two independent facts in the Table 2. FactLogic determined the probability of guilt to exceed 90%, a value much greater than probable cause.

2. More Than One Fact Finder:
Analyze the Probability of Guilt

Independent Evaluations. It is usually said that members of a group should evaluate the evidence independently (i.e., without communication). However, whether independence is desired depends upon the objective:

• Accurate Evaluation. If the objective is to evaluate the evidence accurately, members should evaluate the evidence without communicating (i.e., independently). When a number of officers or officials independently provide their judgments, the corroboration either shows or fails to show that "a reasonably prudent man" has met probable cause.
• Prediction. If the objective is to predict the decisions of a target group (e.g., a jury), members should evaluate the evidence by communicating as will members of the target group (i.e., dependently). If evaluations are dependent, the variation of estimates tends to be smaller than if evaluations are independent.

2.1 Types of Analysis

FactLogic provides the numbers necessary to conduct at least three types of statistical analysis:

Carefully Define the Probability of Guilt. FactLogic defines the probability of guilt by computing the average and computing an interval on both sides of the average within which you can be 95% confident that the true probability of guilt exists.

Compare the Probability of Guilt to Probable Cause. FactLogic determines the probability that is exceeded, with 95% certainty, by the mean probability of guilt. Compare this probability to probable cause.

Compare the Probabilities of Guilt of Two Suspects. FactLogic determines if the mean probability of guilt of one suspect is greater, with 95% certainty, than the mean of the other suspect. See Investigation.

2.2 Examples

Example (Carefully Define and Compare the Probability of Guilt to Probable Cause): Officer Parsons arrested a robbery suspect, believing there was sufficient evidence to reach probable cause. He entered his subjective probabilities for the three independent facts. FactLogic determines the probability of guilt to be 74.991%. He wanted the corroboration of others for the sake of fairness and for justification should the arrest be challenged in court. He asked three other officers to independently (i.e., without communication) evaluate the evidence. They evaluated the evidence, and the resulting probabilities of guilt were 64.226%, 82.828%, and 89.053%.

• Carefully define the probability of guilt
• Compare the probability of guilt to probable cause.

Solution (Carefully Define the Probability of Guilt). The average of the four probabilities of guilt is 77.775%. Analysis shows that Officer Parsons can be 95% confident that the probability of guilt is between 60.746% and 94.804%.

Solution (Compare the Probability of Guilt to Probable Cause). Analysis shows that Officer Parsons can be 95% confident that the probability of guilt exceeds 65.191%, a probability that exceeds probable cause as judged by many.

Summary

The United States Supreme Court recommends determining probable cause by a method such as provided by FactLogic. FactLogic uses your judgments about independent facts to help you to justify arrests, searches, and warrants and to set bail. It provides a result that tends to be more trustworthy than intuition and tends to be that of "a reasonable man."

Single Fact Finder. FactLogic determines the probability of guilt.

More than One Fact Finder. FactLogic determines the probability of guilt with accuracy that is available from multiple fact finders. It allows you to be more certain of

• the probability of guilt,
• the comparison of the probability of guilt with probable cause, and
• the comparison of the probabilities of guilt of two suspects.