Video Evidence 101

Network surveillance cameras help Green Bay schools hone their C.S.I. skills

• By Fredrik Nilsson
• Jan 01, 2013

Public schools may not be a hotbed of criminal activity, but they do have their share of incidents on campus that need to be investigated. Green Bay Area Public School District, the fourth-largest school district in Wisconsin, had been using analog surveillance technology as part of its investigative toolbox for 12 years. But with 24-hour-a-day operation, the multi-school CCTV system had far exceeded its useful life.

With 38 primary and secondary schools spread across 92 square miles, the district needed to upgrade surveillance to better protect its 21,000 students. It was time to search for a replacement solution that not only gave each school the autonomy to view its own video but would also allow the district the flexibility to manage and support the cameras centrally.

Allen Behnke, directory of safety, security and telecom for the school district, decided to retire the old, disparate analog systems and start fresh, reasoning that the advances in digital surveillance technology would easily justify the investment—not only in superior image quality but also ease of use and remote maintenance.

“Initially, we thought we would simply add encoders to the analog cameras to connect them to the LAN/WAN the district already had in place,” Behnke said. “But when we looked at all the advances that digital megapixel technology offered us, it just made sense to scrap the old system and start anew.”

The district worked with SimplexGrinnell, a Tyco business, to design a new system that would replace the old analog CCTV equipment with more than 500 Axis Communications HDTV-quality, fixeddome network cameras controlled by a Video Insight Digital Video Management System (VMS).

Video Insight includes intuitive map and floor plan navigation features that allow administrators to view and clip video from their respective schools, either via their desktop computers using Monitor Station or the Web Client or remotely from iPads and smartphones, while patrolling the campuses.

“Video Insight’s open architecture, ease of use and features that were developed specifically for large systems with multi-campuses and facilities is what made it best-suited for a project such as the Green Bay Area School District,” said James Whitcomb, Video Insight CTO.

The network-based solution was then configured to store video locally at all the secondary schools. For the elementary schools, depending on location, the video streams to central servers on either the east or west side of the district. The school district’s security department maintains full access to all the video servers and cameras, allowing technical staff to adjust camera parameters remotely and update camera firmware globally, avoiding the cost and delay of onsite service calls.

Providing a Better Class of Coverage

While the district’s legacy systems included a mix of analog PTZ and fixed cameras, SimplexGrinnell calculated that replacing them with megapixel fixed-dome network cameras would provide Green Bay campuses with greater coverage. Martin Security Systems, a Wisconsin-based provider of “simplified security systems,” was then contracted to install the IP cameras.

“These newer fixed-dome cameras cover what three of our old [analog] PTZ cameras used to do,” Behnke said. “Part of it is smarter camera placement, but most of the improvement is because these new cameras provide a higher resolution and greater density of pixels as well as a wider field of view.”

Behnke feels that the megapixel fixeddome cameras are a much better deterrent than the district’s analog PTZ cameras because “if a student is thinking about doing mischief, they can’t tell which direction the camera is pointing. Plus, you avoid the problem of the PTZ camera being pointed in one direction when the real event is happening in the opposite direction.”

The outdoor-ready, 1080p HDTV and 5-megapixel network cameras installed on building exteriors and in school parking lots include automatic day/night features and tampering alarms to ensure uncompromising coverage around the clock. The low-profile footprint of the fixed-dome cameras keeps their presence unobtrusive, which was key for a welcoming educational atmosphere. Additionally, the cameras’ high-tolow temperature thresholds and auto-iris control easily accommodate the extreme glare coming off of ice and snow, which is typical of Wisconsin winters.

For interior locations such as hallways, common areas and known hot spots, the district uses 1-megapixel network cameras that also feature automatic day/night operation and tampering alarms.

Many of the cameras are connected to the district’s network via Cat-5 and Cat-6 cabling, except for a few locations such as the back ends of parking lots where the system was augmented with wireless technology to avoid the expense of trenching a fiber line to the site.

Coordinating Forensic Evidence under a Single Surveillance Umbrella

The switch from analog to IP-based surveillance gave district administrators a host of investigative options they never had with their old system.

“Being able to intelligently search the video from the end user’s desktop is huge for us,” Behnke said.

Under their legacy system, users had to go into the server room and sift through hours of footage to find the video they needed.

Remote maintenance was another big plus.

“With our old system, we had to physically go right to the camera to do any adjustments,” Behnke said. “But with the Axis cameras residing on the network, we can log into the surveillance system to troubleshoot, refocus and adjust camera parameters remotely. We can pretty much put a camera in place and never physically touch it again.”

At the end of the day, however, it was the image clarity that really sold the district on its new network surveillance system. Administrators can zoom in on archived images to extract greater forensic detail than was possible with the previous system. Put another way, the HDTV video they pull from today’s fixed IP cameras provides more usable pixels than the old analog PTZs, even if the camera was zoomed in. In one specific case of an attempted break-in, even though the perpetrator’s face was hidden from the new HDTV cameras, local police were able to apprehend the person because his distinctive clothing, backpack and gait were clearly detailed on the video.

Securing the Chain of Evidence

Because the district opted for a distributed storage configuration, Behnke’s team takes utmost care to keep the video archives secure. Leveraging the video management system’s directory feature to control access to the system, Behnke strictly limits principals, associate principals and school resource officers to live and archived viewing of their own respective campuses. In case of emergency, local police are granted similar controlled access. But if someone needs a copy of a particular clip, he or she can receive it only through Behnke’s department.

“For our own protection, we limit the number of people who can export video to an external device,” Behnke said. “It only takes a matter of seconds for something to go viral and create havoc with our district’s reputation, so we restrict that feature to our security technicians only.”

Separating the Guilty from the Innocent

Though the cameras are primarily used for forensic investigation, administrators monitor the cameras live from their office desktops or mobile devices as they walk the corridors of the school.

“Because we have secure login credentials to Wi-Fi throughout the district, the principals, associate principals and school resource officers don’t have to be chained to their desks to see what’s going on in another part of the building,” Behnke said. Both the wireless connection and video streams also have the highest level of logical security built in such as HTTPS encryption, IP filtering and IEEE 802.1x.

As an experienced user of the new IP surveillance system, Curt Julian, associate principal of East High School, finds that having video evidence to support the information he gathers during an investigation helps him and his colleagues determine what really transpired.

“We try to use the network cameras as corroborative tools rather than the sole source of evidence,” Julian said. “But there have been times that the cameras were the only way to determine the true nature of an event.”

In one case, the video revealed that a student had been wrongly accused of pulling a fire alarm immediately before a school concert. The real culprit turned out to be a staff member feeling around for the light switch in a dark gym and pulling the alarm by mistake.

In another case, a student was suspected of stealing a beverage from the cafeteria cooler. The video archives revealed that the student had mastered his pilfering technique by stealing bottles every day for more than a month prior to the day he got caught. Not anymore, thanks to the high-quality video evidence.

During a more serious incident, more than 50 students were present during a large fight in a school hallway. Witness statements conflicted as to who the participants were and who were simply bystanders. Because the fight would likely lead to expulsion hearings, it was imperative to establish the true facts of the incident.

“The video evidence allowed us to corroborate statements and weed out the truth from the lies and misperceptions,” Julian said. “Without the footage, we’d never have broken the code of silence that persisted among the actual participants. We eventually learned that the fight stemmed from a verbal confrontation that took place days earlier. We searched the video archives and were able to document which students were involved from the start.”

“We may not be quite C.S.I. caliber,” Behnke said, “but the speed at which we can search and retrieve video and the quality of images we capture are just phenomenal.”

This article originally appeared in the January 2013 issue of Security Today.