Key takeaways
- Learn how OSINT tools for law enforcement like Sherlock, Maigret, and theHarvester help uncover online leads.
- Discover how open-source intelligence improves digital investigations and community safety.
- See how patrol officers and detectives can use free OSINT tools to connect digital clues faster.
- Understand why digital intelligence training is essential for effective, modern policing.
By Nate Nobel
The world of policing has always relied on intelligence, whether from confidential informants, crime reports, or proactive patrols. Law enforcement is, at its core, an intelligence-driven profession. With the rise of the digital revolution and the widespread use of social media, we are now experiencing an unprecedented saturation of accessible, real-time information. Officers who adapt and learn to navigate this evolving digital landscape will benefit from higher case closure rates, improved ability to identify both victims and suspects, and enhanced situational awareness in potentially escalating incidents.
In this article, I’ll explore three powerful open-source intelligence (OSINT) tools that help make sense of this vast online environment: Sherlock, Maigret and theHarvester.
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Tracking digital identities with Sherlock
Sherlock is designed to locate subjects across the internet using a known username. As creatures of habit, people tend to use the same or similar usernames across multiple social media and online platforms, making this a valuable method for tracking digital footprints.
Sherlock searches through approximately 400 websites to find matching usernames. It can be installed from sherlockproject.xyz and is simple to use. Once installed, you can open a terminal (such as a Bash shell or Command Prompt) and run a command like: sherlock exampleusername
This automatically scans hundreds of platforms and prints any matches directly in your terminal. Sherlock also supports advanced arguments, such as --tor or -t, allowing you to route searches through the TOR network for added anonymity and security.
Sherlock can be especially useful in cases involving internet crimes against children (ICAC), harassment, fraud and even missing persons. By inputting a known username from a tip, witness statement, or report, officers can quickly discover other platforms the individual uses — which can lead to evidence of behavior, patterns, or contacts relevant to the investigation.
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Building digital dossiers with Maigret
Maigret is a tool designed to build detailed dossiers on individuals based solely on their usernames. While it shares similarities with Sherlock, Maigret offers enhanced features that make it particularly valuable for law enforcement investigations.
One of Maigret’s standout capabilities is its ability to parse account pages and extract personal information such as full names, locations, profile images and links to other social media profiles. This feature enables investigators to gather a wealth of information from a single username input.
Moreover, Maigret supports recursive searches — automatically identifying and following links to associated accounts across different platforms. This functionality allows for a more comprehensive mapping of an individual’s online presence.
For ease of use, Maigret can be operated via a command-line interface or through a user-friendly web interface. The web interface provides visual graphs of the search results and options to download reports in various formats, including HTML and PDF. You can learn more and install it from the Maigret documentation.
Maigret has become a go-to tool for more in-depth investigations. If Sherlock is your quick lookup tool, Maigret is your investigative notebook. It helps uncover relationships, affiliations, and alternate online identities that may otherwise go undetected. Whether tracking gang affiliations on social media or monitoring extremist group activity, Maigret empowers officers with more than just usernames — it builds context.
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Conducting digital reconnaissance with theHarvester
TheHarvester is an OSINT tool designed to assist in the reconnaissance phase of investigations. It enables law enforcement professionals to gather critical information about a target domain — such as email addresses, subdomains, IP addresses and hostnames — by leveraging publicly available data sources.
The tool supports multiple search engines and services, including Bing, DuckDuckGo and Shodan. By specifying a target domain and selecting the desired sources, investigators can efficiently collect valuable intelligence without directly interacting with the target system — minimizing the risk of detection.
Once installed, you can initiate a search with a command like: theHarvester -d example.com -b all
This command searches for information related to example.com across all supported platforms and presents the findings in the terminal. Results can also be exported in various formats, including HTML and XML, for deeper analysis and reporting. The tool is available on GitHub.
In cybercrime investigations, theHarvester can reveal previously unknown infrastructure or digital assets connected to a suspect. It can also help identify targeted phishing campaigns, fraudulent websites, or digital footprints left behind during a crime. It is particularly valuable for detectives working with limited information or when mapping out the technical infrastructure used by a suspect.
Why OSINT matters for every officer
While these tools are often associated with detectives or cybercrime units, their utility extends all the way down to the patrol level. Officers on the street encounter digital clues constantly — whether it’s a username scribbled on a notebook, a suspicious email in a domestic case, or a complaint about online threats. Knowing how to quickly look up usernames or domains using these tools can give patrol officers actionable intelligence before they even clear the call.
Integrating OSINT training into basic academy instruction or annual in-service would dramatically improve frontline officers’ ability to collect leads, protect victims, and build stronger initial cases. OSINT tools are free, accessible and easy to use with a little practice — making them ideal force multipliers for any agency.
The future of digital policing
In today’s evolving digital landscape, the success of modern law enforcement depends on more than just traditional tactics — it requires a willingness to adapt. Investigators who embrace open-source tools and digital techniques gain access to an immense wealth of publicly available intelligence, often in real time.
From tracking usernames across platforms to mapping digital footprints and uncovering hidden connections, these tools empower officers to act faster, build stronger cases and ultimately protect their communities more effectively. The digital world isn’t just the future of policing — it’s the present, and those who fail to adapt risk being left behind.
Training discussion points
- How can OSINT tools be safely integrated into day-to-day patrol operations?
- What policies or training should agencies develop to ensure ethical use of OSINT?
- How can small departments with limited resources make OSINT adoption practical?
- What challenges do investigators face in verifying the accuracy of open-source data?
Tactical takeaway
Train every officer, not just analysts, to use free OSINT tools; the payoff in case development and victim protection is immediate.
How is your agency preparing officers to handle digital investigations and use open-source intelligence effectively? Share below.
References
- Sherlock Project. (n.d.). Sherlock: Hunt down social media accounts by username across social networks.
- Maigret Documentation. (n.d.). Maigret: Collect a dossier on a person by username from thousands of sites.
- laramies. (n.d.). theHarvester – Gathering e-mail accounts, subdomain names, virtual hosts, open ports, and banners. GitHub.
About the author
Nate Nobel is a senior computer forensics instructor for the Federal Law Enforcement Training Centers (FLETC) and a former law enforcement investigator specializing in cyber crimes, digital forensics and open-source intelligence (OSINT). He is the founder of Operation // NODE, a nonprofit organization dedicated to empowering law enforcement with the tools and training to investigate cyber crimes such as online exploitation and ICAC offenses. Nate is also the creator of the training programs Cyber Crimes for Street Cops and Undercover and Sock Puppets, which provide practical instruction for modern digital investigations.
