Unveiling the jigsaw puzzle

Forensic scientists, or criminalists, are scientists that apply their expertise and knowledge to law enforcement.

According to the United States Justice Department, the role of a forensic scientist is to “examine and analyze evidence from crime scenes and elsewhere to develop objective findings that can assist in the investigation and prosecution of perpetrators of crime or absolve an innocent person from suspicion.”

A forensic scientist works in conjunction with local police. They provide scientific evidence to assist a case but are not obligated to support a certain narrative.

“We are not here to imprison criminals. We are here to state the facts so that it can lead to a conviction or an exoneration,” said Cindy Anzalone, a forensic scientist and DNA analyst with San Mateo County Forensic Laboratory. 

Appropriately punishing a perpetrator is far more complicated than what is shown on television. Forensic scientists must produce hard and indisputable evidence to properly prosecute or forgive someone for a crime. Thus, district attorneys and law enforcement agencies turn to forensic scientists to analyze evidence to create a valid conclusion.

“A forensic scientist is a scientist that works in the realm of law enforcement. We are not cops, we are not detectives, we are scientists. We are in the laboratory 90% of the time, and we all have degrees in physical science, so like biology, molecular biology, or chemistry,” Anzalone said.

However, a case can only proceed to the forensic scientist or the courtroom once it has been reported to and investigated by the local police department. 

Depending on the crime, the police department or local sheriff’s office will respond accordingly to secure evidence and the crime scene to conduct their investigation.

“One of the most common crimes in San Mateo County is burglaries, and typically we will respond by collecting fingerprints off doorknobs and maybe evidence from broken glass,” said Antoine Abinader, an officer for San Mateo County Sheriff’s Office and School Resource Officer for Carlmont High School. “When there’s a major crime scene like a homicide, we have a protocol for it. Basically, we will lock down that area, we will gather as much information as we can, from the basic tests we can run and noting down witnesses and who enters and exits the scene.” 

Often, the police have to get a search warrant to have access to objects or areas that can be considered private. These objects or areas that are searched are then used as evidence. 

“Search warrants are anything from a cell phone to a car to a house. Sometimes you have to write a search warrant to collect somebody’s blood because they’re refusing to do it,” Abinader said. “We need to write a very detailed warrant saying why we want to go to this person’s home or why we want this person’s cell phone and be able to access all their data, and that all gets presented to a judge who then decides whether that’s enough to be that intrusive on a person’s personal space and property.”

Police have the power to access local cameras for recordings during the crime and can interview witnesses with their consent. Once they have exhausted all avenues of investigation, they turn to criminalists, like Anzalone, for further analysis and research. 

The job of convicting a criminal falls on the District Attorney’s office. As prosecutors, their job is to gather information regarding a reported crime, using forensic analysis and the police investigation to conclude by filing criminal charges against someone or dismissing the case entirely. 

Morris Maya, an assistant district attorney for San Mateo County, oversees most cases of domestic violence, elder abuse, gang, prosecution, homicide, and electronic crimes. Maya and his fellow district attorneys often rely on forensic science to understand a case in its entirety before proceeding. 

“District attorneys use forensic evidence, not just to build the cases, but we also use it to understand if we’re right or wrong about who we might suspect is responsible for a crime,” Maya said.

As criminal prosecutors in California, the district attorneys must have “proof beyond reasonable doubt” or almost absolute certainty that a person is guilty. 

“We try to make a preliminary assessment as early on as we can because the filing of criminal charges against someone is no small thing. And filing charges can do a lot of damage to someone by just filing a case against them. Even if it gets dismissed soon thereafter, you can imagine the amount of reputation damage that someone might suffer if they get charged with a really horrible crime,” Maya said.

As Maya makes his judgment, he scrutinizes the evidence further by verifying the sources and experts that presented the evidence to him. 

“I have to believe that the evidence is sound; I have to believe that the expert who I’m using is qualified; I have to believe that it has been peer-reviewed and, you know, stands the test of scrutiny. Only then will I be able to endorse it as a prosecutor and use it to try to convince the jury,” Maya said.

Once charges have been filed, Maya and his team of attorneys move to present their case in front of the jury. A criminal trial can last for multiple years as new evidence pour in. What’s more, unlike a civil court where only a majority of the jury reaches a settlement, a unanimous verdict is required to get a unanimous verdict of guilty or not guilty. 

“As a practical matter, when the jury is unable to reach a unanimous verdict, that is what lawyers refer to as a hung jury, or when a jury has deliberated for a sufficient amount of time, and there is no hope of movement or progression,” Maya said. “When that happens, the judge declares a mistrial or that the case has no resolution. Depending on the split of a jury or the ratio of guilty to not guilty, we can move to retry the case in court or dismiss it.”

Ultimately, the district attorney can continue to retry cases with new evidence and developments. Doing so can present evidence to achieve the correct verdict. 

“There’s no benefit in holding the wrong person accountable. And not only is there no benefit, but there’s also real damage being done. When we do that, we harm someone with no culpability; that’s a terrible outcome. So when you understand what a prosecutor does, you can understand why forensic science is a really helpful tool in both incorporating a person who’s involved incriminating, you know them if they’re involved, but also exonerating people who aren’t involved,” Maya said.