Case Study: Extracting And Analyzing Messenger Data With Oxygen Forensic Detective

by Nikola Novak

It‘s a great pleasure to share my experience of working with Oxygen Forensic Detective, which was a crucial tool in solving one of my cases.

A father of a minor girl contacted me, worried his daughter was in suspicious society and probably had been consuming marijuana. His wife accidentally found traces of a substance which looked and smelled like marijuana in his daughter‘s clothes and that led him to that conclusion.

Polygraphic testing pointed that the girl was intensively communicating with her friends mostly via Facebook and mobile messenger apps, so I suggested to her parents to thoroughly examine her phone, believing they would found incriminating evidence.

The parents reached me a day later and told me they examined the messages in all the installed apps and that they hadn‘t found any message that would justify their doubts, so they assumed the messages were deleted after the polygraphic testing.

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I suggested a forensic analysis of a mobile phone: Tesla Smartphone 6.4 Lite. After her parents insisted on that, the girl reluctantly agreed.

After physical acqusition I focused on analysing the data from the messenger apps and I noticed that a complete communication from Viber app had been deleted.

Photo.1: Recover deleted Viber messages

Oxygen Forensic Detective successfully retrieved all deleted data, among which even 4652 Viber messages which were crucial in finding incriminating contacts and reconstruction of her movements. I have to admit I was fascinated by the result because I didn‘t expect that number of retrieved messages.

By using Oxygen Forensic Detective analytical tools I quickly filtered Viber communication and presented the contacted people, frequency of communication as well as the content of the messages to her parents in a simple way which I delivered to them in the form of very clear PDF report.

Photo 2: Analysis of Viber communication

Mobile devices are an important part of our lives and unavoidable subject of our inquiries. In most of the polygraphic tests a trace leads me towards mobile phones and because of that Oxygen Forensic Detective is a necessary additional tool in my work.

Photo 3: Reconstruction of movements

Find out more about Oxygen Forensic Detective at

About Nikola Novak

Novak started his career early, as a student, while working in investigation agency Protecta as an associate investigator, where he learned the basic tactics of secret surveillance from ex secret service agents. Novak later became a private investigator in the agency, and advanced to the level where he managed the private investigations unit department. Novak has over a decade of experience working in the private security industry. In his career Novak has worked on more than 3,000 private investigation cases and conducted more than 1,000 polygraph examinations worldwide.

Mr. Novak is president and founder of Security and Education Association of Serbia, which gathers all the agencies from the private security sector in Serbia and organizes post-secondary education classes and specialized training courses for people who operate in the private security, polygraph and investigations industry. Novak is also founder and director of the European Polygraph Academy, which conducts basic polygraph examiner training using APA standards and continuing education for polygraph examiners worldwide. The European Polygraph Academy is the first polygraph education institution of its kind to be created and operational in continental Europe. Mr. Novak is also a course coordinator for the courses held in the European Polygraph Academy, where he also works as a co-instructor and teaches the students who attend the basic polygraph examiner training course. Mr. Novak is a member of every relevant international association – World Association of Detectives, International Association of Private Detectives, American Polygraph Association, European Polygraph Association, British and European Polygraph Association, National Polygraph Association and European Society of Criminology.

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