Securing the Crime Scene
Police arrive at a home where a person has been found deceased. Before investigators begin collecting evidence, what should officers do first?
Secure the scene and check for threats.
Evidence can help the ______ and ______ build their cases.
Prosecution and defense.
A strand of hair is recovered from a crime scene.
Biological evidence.
Police find a phone at a crime scene. Investigators want to examine the owner's private messages. Can they automatically read everything on the phone simply because they found it?
No. Private digital information generally requires appropriate legal authorization.
A suspect tells police, “I was at home watching TV when the crime happened.” What is the suspect providing investigators?
An alibi.
Police arrive at a possible burglary. The front door is open, but there is no indication that the suspect has left. Should investigators immediately begin searching every room? Explain.
No. They must first consider safety and secure the scene before beginning the investigation.
An investigator finds a knife on the floor. Before picking it up, what should happen first?
The item should be photographed/documented before collection.
A security camera records someone entering a building at 11:42 p.m.
Digital evidence.
Investigators find a public social-media post showing a suspect at a particular location. Do they generally need a warrant just to view information that is publicly available?
No. Publicly available information can generally be viewed without accessing private content.
A burglary occurred at 8:15 p.m. A suspect claims he was at a movie theater. A theater receipt shows he purchased a ticket at 7:40 p.m., but there is no evidence showing he remained inside the theater. Is the receipt alone enough to establish his alibi?
No. The ticket proves he purchased a ticket, but it does not prove he was still at the theater when the burglary occurred.
A crime-scene boundary has been established, but an officer allows a friend of the victim to enter because the friend says, “I only need to grab my purse.” What is wrong with this decision?
Only authorized personnel should enter because the person could disturb or contaminate evidence.
A detective finds a wallet on a table. The detective records the date and who collected it but does not record where it was found. What important information is missing?
The location of the evidence.
A witness tells investigators that they saw someone running away from the building.
Testimonial evidence.
A blood sample is collected by Officer A. Officer A gives it to Technician B. Technician B sends it to the laboratory. What information should be recorded about these transfers?
Who handled/transferred the evidence, when it was transferred, and the appropriate handling/storage information.
A robbery occurred at 9:00 p.m. A suspect claims she was at a restaurant from 8:30–9:30 p.m. A security camera shows her entering the restaurant at 8:32 p.m. and leaving at 8:47 p.m. Does the footage completely support her alibi?
No. It confirms she was at the restaurant during part of the claimed time, but she left before the robbery occurred.
A detective arrives at a crime scene and notices that several officers, a paramedic, and a witness have already entered. What document should investigators use to determine who entered and exited the scene?
The scene entry/exit log.
An investigator collects a piece of evidence and places it in the wrong type of container. Why could this be a problem even if the investigator correctly identified the evidence?
Improper packaging can damage or contaminate evidence.
Investigators recover a shoe, a broken window, and a piece of fabric from the scene. What type of evidence do these items primarily represent?
Physical evidence.
Investigators believe a suspect's private phone records may contain information related to a crime. Before requesting a warrant, an officer prepares a written statement explaining the facts and evidence that support the request. What is this document called?
An affidavit.
A crime occurred at 7:45 p.m. A suspect says he was at home. His phone connected to his home Wi-Fi at 7:40 p.m., but a store's security camera shows him entering the store at 7:43 p.m., which is only five minutes from the crime scene. What does this tell investigators?
The evidence conflicts with the alibi. The Wi-Fi connection supports that the phone was at home, but it does not necessarily prove the suspect was at home. The security footage places the suspect somewhere else shortly before the crime.
Investigators arrive at a suspected burglary. Before collecting evidence, they notice an open back door, broken glass, an overturned chair, and an unfamiliar vehicle parked outside. What are these observations an example of?
Initial observations or preliminary assessments.
Two different pieces of evidence are collected from separate locations. An investigator uses the same contaminated gloves to handle both items. What specific problem could this create?
Cross-contamination, because material from one item or location could be transferred to another.
Investigators recover a phone containing text messages, a bloodstained shirt, and a witness's written statement. Identify the evidence type for each.
A defense attorney questions whether a piece of evidence presented in court is the same item originally collected at the crime scene. Investigators have documentation showing the item was collected, transferred, analyzed, and stored by specific people. What does this documentation help establish?
The chain of custody.
A robbery occurred at 8:15 p.m. A suspect claims he was at a restaurant across town. Investigators know:
Based on this timeline, does the evidence support the suspect's alibi? Explain your answer.
Yes. The evidence supports the alibi because multiple time-stamped records place the suspect at the restaurant before, during, and after the 8:15 p.m. robbery.