(NewsNation) — Many people are wondering why police still can’t name a suspect a month after the gruesome quadruple homicide of four University of Idaho students.

The investigation is delicate, and detectives need extensive training. NewsNation was give an exclusive tour inside the Global Forensic and Justice Center at Florida International University to understand how evidence would be collected at a crime scene.

The university’s mock crime center has hosted thousands of police officers and military investigators for training since its opening in 2018.

Students learn to first secure the crime scene and prevent contamination. Next, they do a walk through and prioritize collection. Some evidence is perishable and can get warm, melt or be washed away in the elements. After that, photos, video and 3D imaging are taken. That’s all before collecting a shred of evidence to be analyzed for biologics, DNA and digital forensics at a lab.

”If it’s a much larger house with a transient population, you’re having people depositing information over periods of time … It may, or may not, be relevant to the crime scene, but the professional has to collect what they believe, may solve or give answers to what happened at that house,” said Kevin Lothridge, executive director of the center.

That’s exactly what detectives in Moscow, Idaho had to contend with: A well-visited, sprawling home set into the hillside. In the college killings, digital forensics are presumably playing a major role.

The training center showed how carefully cellphones, tablets and computers are taken from a scene and brought to a lab.