Criminal Investigations: Techniques and Legal Boundaries

You may be familiar with criminal investigation techniques from television shows. In a TV show, the criminal process from the crime and conviction only takes an hour. In reality, criminal investigations generally take much longer.

There can also be problems along the way. The police department may make mistakes that violate a suspect’s rights. Criminal defense attorneys can fight to protect their client’s rights and make sure they get a fair trial.

If you have questions about the investigation in your criminal case, contact a criminal defense lawyer for legal advice.

What Are the Steps in a Criminal Investigation?

A criminal investigation generally starts with a crime or suspicion of criminal activity. During the investigation, the police and prosecutors work together. They identify the crime, who they believe committed the crime, and gather evidence to try to earn a conviction in court. The steps in a crime investigation may include:

• Crime scene investigation
• Gathering evidence and documentation
• Interviewing witnesses and victims
• Identifying suspects and surveillance
• Obtaining probable cause to make an arrest

What Are Common Mistakes in Criminal Investigations?

The criminal justice system has legal protections to make sure each person has due process under the law. Under American criminal law, you are innocent until proven guilty. The prosecution has the burden to show you are guilty beyond a reasonable doubt. That means if you are under investigation, you are still not guilty of a crime in the eyes of the law.

Unfortunately, sometimes law enforcement agencies don’t follow the rules. If police investigators search for physical evidence without a warrant, it may be a violation of your search and seizure rights. If law enforcement officers violate your rights during the investigative process, your attorney can fight to get the evidence thrown out.

Your attorney will closely review any evidence to identify problems with the police agency investigation. They will also look for their own evidence that casts doubt on the prosecution’s case.

Crime Scene Investigation

Many criminal investigations begin with looking at the crime scene. Police officers try to identify what happened and any parties involved. This can include the alleged victims, alleged perpetrators, and witnesses. In a simple case, the defendant may still be at the scene and admit to committing a crime.

Forensic Tools and Gathering Evidence

Police will gather evidence of the crime to use in the investigation or to present at trial. Police may also use forensic science to get more information and evidence. Forensic scientist techniques in criminal cases can include:

• Fingerprinting
• DNA tests
• Ballistics
• Blood analysis and bloodstain patterns
• Toxicology tests
• Computer forensics for cybercrime cases

When this evidence is gathered, it should also be carefully recorded. Losing track of the chain of custody of the evidence could mean that someone tampered with it.

Interviewing Victims and Witnesses

Investigators may talk to the victims and any witnesses to gather more evidence. Witnesses can provide first-hand testimony of what happened and what they saw. Witness details can help identify the suspect, vehicles, and other evidence.

Officers should use proper techniques when talking to witnesses. This includes not telling witnesses what to say or improperly identifying suspects. For example, if the police conduct a lineup for witness identification and indicate that they want the witness to pick a specific person, that could be a violation of the defendant’s due process rights.

Surveillance and Search Warrants

For serious crimes, the FBI or other agencies may conduct surveillance to identify suspects and gather evidence. In the U.S., you generally have a right to privacy. With few exceptions, police cannot search your home or areas where you have a reasonable expectation of privacy without a search warrant.

A search warrant requires showing a judge there is probable cause to believe there is specific evidence of a crime in a specific location. The police also need probable cause to make an arrest. Without probable cause, any constitutional violations could damage the prosecutor’s case.

Presenting Evidence at Trial

The prosecutor has to have enough evidence to prove all elements of the crime beyond a reasonable doubt. However, before trial, your attorney can file pretrial motions. These motions can try to suppress evidence, limit witness testimony, and make sure you receive a fair trial. If your attorney can challenge enough evidence, the prosecutor may not have enough to prove their case beyond a reasonable doubt, meaning the charges will be dropped.

How a Lawyer Can Help When the Investigation Was Unconstitutional

A criminal defense lawyer can review your case, look at the evidence, and the way police conducted the investigation. Whenever there are problems with the investigation, your attorney can challenge the admissibility of the evidence. The prosecution should not benefit from their wrongdoing.

If you have questions about your legal rights in a criminal investigation, talk to an experienced criminal defense lawyer for answers as soon as you learn you are under investigation.