Road patrol and detective work are different sides of the same coin. Both divisions perform many of the same functions but in different ways and at different levels. Conducting an area canvass is one such example.

An area canvass is a thorough search for possible leads in a geographical area around the vicinity of a crime through personal interviews of people within that area. The interviews are specific to the investigation that is underway and are documented for record. Typically, an agency has a lot more road patrol officers than it does detectives, so the initial area canvass is usually done by road patrol. A second, or follow-up area canvass is done by detectives based on the information obtained.

An area canvass done right can be the most important investigative tool in developing leads and solving cases. Knowing how to work it right is the key.

A Lot Like Fishing
I'll use a fishing analogy to explain further. In the first area canvass, road patrol casts a large fishing net in hopes of catching any fish. Since they don't know where the fish are, they continue to cast their net until they find small pockets of fish. Everyone who goes fishing knows small fish lead to bigger fish. The goal is to get enough information from working the small pockets of fish to learn where the big fish are. During the second (follow-up) area canvass, detectives continue to work those small pockets of fish until they find where the big fish are. Sometimes road patrol's net catches a big fish, and detectives know to go right there first.

You search an extended area around your crime scene looking for leads you can use immediately or pass them on to detectives for further development. If you work your area canvass right, you will find enough information to lead you to what you're looking for.

Tips for Officers
Ideally, you are searching for an eyewitness to the crime. If you can't find an eyewitness, then you need someone who heard something of material value. Here are some points to remember when conducting your canvass.
• All-In. We have to realize that area canvass is a critical assignment and not to be dismissed as a menial or lesser task. All tasks contribute to the solving of the investigation, no matter the role you think you play. If you downplay the significance of the canvass, you won't give it the attention it deserves and you will miss something. It needs to be an all-in attitude from beginning to end. 
• Take Your Time. In firearms training you learn that shooting fast and shooting accurately are not the same thing. If you rush through an area canvass you will do a poor job. You need to conduct your interviews professionally and thoroughly. If you miss something you may never see it again. Time takes care of itself. You take care of your investigation.
• You Canvass People. You are dealing with people, not locations. Don't think that just because you speak to one person in a residence you can check the place off your list. Speak to everyone there. If you identify someone who is not there, you need to find out where they are and arrange to speak with them at another time. Always document what you did or didn't do to avoid duplicating efforts.
• Interview Separately. Remember Interviewing 101: You interview everyone separately. Eyewitnesses or people who have heard specific things will submit to groupthink when not alone. They will look to the informal leader and follow them. They will also wait to see what the group is saying. Finally, if they are alone with you, no one can be sure what they said.
• Document Everything. Document every location, who was there, and who spoke with you. If no one was home, document that for follow-up. Future actions will depend upon your work product. Time is never on our side, so don't waste it by causing someone to have to duplicate your efforts.
• Watch Your Questions. Remember, you are casting out your net for information. Don't limit yourself to the day of the event. You are ruling out the possibility that the suspect has been there before. It's not "Did you see or hear anything suspicious today?" It's more like, "Has anything happened recently to raise your suspicions that something unusual was going on?"

Spread out and canvass in teams assigned to different sections of the area to be covered. Photo: Zuma Press

Tips for Supervisors

Clearly, an area canvass can't afford to be conducted in a haphazard way. It must be organized, documented, and above all else supervised. Supervisors need to pay attention to the following points.
• Assign a Canvass Supervisor. Unless it's an investigation that's being handled by one officer, someone needs to oversee the area canvass. Most of my time as a sergeant, I performed that task alongside my other duties. On larger cases, like a missing endangered juvenile, the area was so large we had to establish canvass teams and each team had someone in charge of the team. There can only be one person directing the overall effort, however. There should be no confusion as to who is in charge, who to report to, and what each person's assignments are.
• Canvass in Chunks. As a supervisor, you should break up your canvass into manageable chunks. Each chunk is a geographical area and only assigned to one officer or team at a time. This prevents duplication of effort. More chunks can be added or taken away based on new information and how it's evaluated.
• Ensure Documentation. Make sure that all interview attempts are documented and reported in a timely manner. No information is deemed unimportant until someone can process it as so. Even then, it's kept because circumstances tend to change and what's not important now may be in the future as new leads develop.

Final Thoughts
Conducting an area canvass is part of Cop 101. Whether the crime is a residential burglary that's over with or a kidnapping, the principles are the same. You must find and interview people within the vicinity of the crime scene who may have something material to contribute to your investigation.

Though retired, I still teach report writing at our regional police academy and emphasize the importance of conducting an area canvass during class. I teach our recruits to look toward the four basic directions as their initial guide. I ask that they try to contact anyone in front of, behind, and to both sides of their crime scene. You can expand out or subtract from the area if need be. For example, if you're at a hotel, there may only be rooms to either side of the victim's.

An area canvass done right can be the most important investigative tool in developing leads and solving cases. It's up to you to do it right, or else possibly lose the only opportunity you have to solve the case.