Search Keywords in PDF With Guide to Find Multiple Terms

search keywords in pdf during forensic examination
Published By Mohit
Anuraag Singh
Approved By Anuraag Singh
Published On April 2nd, 2024
Reading Time 7 Minutes Reading
Category Forensics

Want to search keywords in PDF documents? Go through the write-up and get the complete procedure for doing so.

PDFs continue to be one of the most popular forms of presenting information digitally. People use it to store all types of information, from contracts and reports to emails and scanned documents. 

Its widespread use makes it a prime evidence candidate. So it’s not a surprise that many investigators look for ways to find terms in PDF documents. These small texts can go a long way in solving complicated cases. 

However, many investigators might realize that the simple search mechanism is not enough to get the information that they need. So in this blog, we teach the ways to carry out a complete fact-finding of digital documents accumulated from a crime scene. Let’s start by understanding the basics of searching for keywords in PDFs.

Find Keywords in PDFs the Traditional Way

Looking for keywords is not limited to the forensics arena. Many regular users also want to find them for all sorts of tasks. That’s why all PDF viewers, whether desktop-based or browser-based include a searching capability.

Also Read: Understanding the Microsoft Teams Forensics Approach 

Note: The following steps are for a Windows machine. If you are searching for a keyword on a Mac, replace the Control key with Command.

  • Once you have your PDF open, press the Ctrl + F key together.
  • This opens a small search bar (usually at the top right corner).
  • Type the keyword you want to view and press Enter.
  • Your PDF viewer should highlight all instances of that word. 
  • Use the arrow icons to jump between the locations where that term is used.

This method is easy but limited in its capability. It can only find the exact word and that too if the PDF is readable.  

In a scenario where there are thousands of PDF files, some of which are scanned copies of real-world data, this search may not give all the data you need. Before we reveal more advanced search tactics, a question often arises.

Why Search Terms in PDF At All?

Despite so many advances in digital forensics, investigators still rely on the age-old practice of term searching in PDFs for the following reasons:

Identifying Relevant Documents:

Evidence seized during a raid is massive. Reading through all the documents one by one is not humanly possible. However, if investigators fix their focus on a particular set of terms, they can analyze the digital data quickly. Likewise, it helps in segregating the useful PDFs from the bloat. So investigators can narrow down the scope of documents they need to examine in detail.

Uncovering Connections and Patterns

Digital crime has evolved to become a sophisticated industry. That means the people on the wrong side of the law often communicate in code words and are spread over a large geographic area. The keyword analysis gives investigators a peek into the minds of criminals. With this, they can start to make a map and establish connections between the entities involved.

Verifying Information 

Detectives who do a keyword search can then tally their findings based on what they get from other sources like witness statements, interviews, etc. This can help in verifying the evidence or identifying discrepancies. Moreover, searching is not just for content but metadata as well. As it helps to determine the authenticity of the evidence and also establish a timeline of the events.

So all these complicated requirements need approaches that go beyond the simple search. So let’s see what other searching options are out there that can help investigators gather the data they need. You can only search one keyword/phrase at a time, and that too in a single document.

Merging all documents into one and conducting a search is no practical response either. Slightly advanced searching options are available in Adobe’s Pro PDF viewer. So let’s see what they are.

Use Acrobat to Find Keywords in PDF

The following steps are for Adobe Acrobat 9 

  • Click the small downward pointing arrow on the right side of the find bar.
  • There are a few options to refine the search criteria. If they don’t fulfill your requirements, select Open Full Reader Search.
  • It opens a separate window. First, there is a set of radio buttons, one for the current document and the other for the entire folder. You can only select one of these options at a time.
  • Below the horizontal separator, you will find a link called Use Advanced Search Options. Click on it. Using this, you can search for multiple keywords in a PDF separated by a space.
  • If you select the folder option, then. You get a maximum of two extra fields to add to your search criteria. These are the metadata options of the document you wish to analyze. 
  • Depending on the option you select, you can get results that contain any one or all the keywords. Note that the boolean operator here is a single-layer.

Also Read: Find Video Attachment in Gmail for Digital Data Analysis

The free Adobe Acrobat limits many of the searching features, and The paid version is not a one-time buy but a subscription-based model. It lacks some important search options we discuss ahead.

Different Ways to Find String in PDF Files

The general search is limited in scope. That is why these techniques are used by forensics experts to get the information they need out of PDF files. 

Fuzzy Search: It helps overcome typos or OCR errors that might otherwise hinder your search.

Wildcards: They help account for variations in spelling or terminology used within documents.

Regular Expressions: They offer granular control for crafting intricate search patterns to pinpoint specific information.

Proximity Search: It allows you to identify potential connections between seemingly unrelated keywords.

Stem Search: It is a more refined version of wild card search in which words containing similar subsets are all searched together.  

Lucky for you the utility we are about to describe includes all these search options, along with many other advantages. 

Steps to Search Multiple Keywords in PDF Professionally

The utility is none other than MailXaminer, which is by far the best tool for conducting forensic analysis of any kind. Use it to see how easy the search keywords in the PDF task are. For that here are the steps. 

  • Open the tool Make a new case 
  • Add PDF evidence. Note: If you have PDFs in the form of email attachments, then you can toggle the OCR for a more in-depth.
  • Once the PDF is uploaded, go to the Search tab.
  • Toggle the “Show Custodian Panel” option, and there you get the keyword menu.
  • Click on the + icon at the top.
  • The first-time keyword addition screen is a little different. Otherwise, all other options remain the same.   
  • Click on “Add Keywords” and type your keywords one by one or add a premade CSV.


With this write-up, investigators now have the full knowledge needed to search keywords in PDFs independently. Here we saw that, after the preliminary examination, a traditional search cannot keep up. As a result, it is better to rely on the automated software. Therefore, the clear-cut way to speed up the investigation is to utilize the advanced searching capabilities of modern forensic utility. 


Q. Is there a keyboard shortcut to bounce between the instances where my keyword occurs inside a PDF?

Yes, you can press the Enter key to go to the next occurrence and use Shift + Enter to return to the previous one.

Q. Can I toggle the advanced search options window in Acrobat directly from my keyboard? 

Yes, you can also use the keyboard shortcut Shift + Ctrl + F to get there directly.

Q. Why do fellow investigators prefer to search keywords in PDF using a forensics tool?

This is because the tool provides a complete solution from start to finish. PDFs from various sources can be loaded together. A report can be generated post-analysis.

Q. How can keyword finding done if the source PDF is encrypted?

The Utility mentioned above contains provisions to remove encryption from source data. After which, you can continue to find keywords as usual.


By Mohit

He has over 4 years of experience as a professional content writer. He is a tech enthusiast who specializes in explaining complicated technical concepts.