Witness 9: Atikur Rahman

Evidence given by Atikur Rahman

My name is Atikur Rahman. Current age is 34 years. Address: [redacted] Mymensingh.

I am working as a Sub-Inspector in the CID, Dhaka. Under serial number 130, dated 6-10-2024 of the Complaint Register of the International Crimes Tribunal, and on the basis of Case No. ICTBD Case No. 8/25, I received two items of evidence from the Investigation Agency:

• • Evidence 1: Disputed voice recorded on a TwinMOS 64 GB pendrive.
  • Evidence 2: A Verbatim DVDR 4.7 GB in which the sample voices of Salman F. Rahman, Zunaid Ahmed Palak, Anisul Huq, Dr. Shirin Sharmin Chaudhury, and Sheikh Rehana are preserved, and it was received by the Digital Forensic Lab, Dhaka for examination.

According to the assignment from the higher authorities, I commenced the examination work on 8-10-25.

Four disputed audio records were found in Evidence No. 1. In a comparative examination, a match was found between the disputed male voice preserved in Evidence 1 and the sample voice of Anisul Huq preserved in Evidence 2.

In a comparative examination, a match was found between the disputed male voice preserved in Evidence 1 and the sample voice of Zunaid Ahmed Palak preserved in Evidence 2.

In a comparative examination, a match was found between the disputed male voice preserved in Evidence 1 and the sample voice of Salman F. Rahman preserved in Evidence 2.

In a comparative examination, a match was found between the disputed male voice preserved in Evidence 1 and the sample voice of Sheikh Rehana preserved in Evidence 2.

In a comparative examination, a match was found between the disputed male voice preserved in Evidence 1 and the sample voice of Shirin Sharmin Chaudhury [Note: user text says male voice, likely a clerical error in original notes for female voices] preserved in Evidence 2.

This is my expert opinion, see Exhibit 1 series documentary proof of expert opinion. Both pages of my opinion bear my signature, and every page of the 23-page attachment bears my signature, Exhibit 1 series.

This is that TwinMOS 64 GB pendrive (Material Exhibit, I), this is that Verbatim DVD R 4.7 GB (Material Exhibit, II).

29 June

Upon comparative examination, the questioned male voice preserved in Exhibit-1 was found to match the specimen voice of Anisul Huq preserved in Exhibit-2. The likelihood ratio obtained during the examination was 159.20.

Upon comparative examination, the questioned male voice preserved in Exhibit-1 was found to match the specimen voice of Junaid Ahmed Palak preserved in Exhibit-2. The likelihood ratio obtained during the examination was 21.02.

Upon comparative examination, the questioned male voice preserved in Exhibit-1 was found to match the specimen voice of Salman F. Rahman preserved in Exhibit-2. The likelihood ratio obtained during the examination was 23.93.

Upon comparative examination, the questioned male voice preserved in Exhibit-1 was found to match the specimen voice of Sheikh Rehana preserved in Exhibit-2. The likelihood ratio obtained during the examination was 18.37.

Upon comparative examination, the questioned male voice preserved in Exhibit-1 was found to match the specimen voice of Shirin Sharmin Chaudhury preserved in Exhibit-2. The likelihood ratio obtained during the examination was 61.21.

This is my statement.

Cross examination by defence counsel Polash Chandra.

I obtained a Diploma in Computer Science from the Institute of Science and Technology, Dhanmondi. I also received training in this field in South Korea.

I do not recall the address of the Institute of Science and Technology in Dhanmondi.

Most probably  I obtained the diploma from the Institute of Science and Technology in 2023. The diploma programme commenced in 2020.

I completed the diploma course during my service with the approval of the competent authority.

During service, officers who are technically proficient are selected to receive specialised training both at home and abroad.

I received practical training at the CID Training Unit and at our Digital Forensic Laboratory for approximately one year. Thereafter, we began providing expert opinions. The training process is still ongoing.

The diploma programme at the Dhanmondi institute was a part-time course.

I will be able to produce documentary proof of the permission granted to pursue the diploma course at a later stage.

The duration of the diploma programme was two years.

I successfully completed the diploma examination, although I do not remember my exact result.

The institution from which I obtained my diploma is still located in Dhanmondi.

It is not true that the institution which awarded my diploma certificate is a fake institution.

It is not true that I did not receive any training from the Institute of Science and Technology.

Prior to joining the police service, I obtained Bachelor’s and Master’s degrees in Islamic Studies from the University of Dhaka.

Before joining the police service, I studied in a madrasa. I obtained my Dakhil certificate from Chakrampur Fazil Madrasa, Trishal, and my Alim certificate from Tamirul Millat Kamil Madrasa, Tongi.

I studied in the Science stream at the Dakhil level and in the Humanities stream at the Alim level.

I joined the Bangladesh Police as a Sub-Inspector in 2019.

Since the beginning of my service, I have been serving in the Criminal Investigation Department (CID).

I have received multiple training in IT Forensics, including several conducted by the Detective Training School.

Several of the institutions from which I received IT-related training possess international recognition.

I do not know whether the institutions from which I received IT training have ISO certification.

I do not know whether my training has ISO certification. I also do not know whether ISO protocols were included in my training.

[Objection raised by prosecution on the ground that can the defence raise questions against any govt institution?
Tribunal: Of course, they can.]

I do not know what ISO is.

I conducted the examination relating to this case at my office laboratory. I do not know whether the laboratory has ISO certification, although it has international recognition.

I do not know the source from which the contents of Exhibit-1 and Exhibit-2 were collected.

For extracting the data contained in the exhibits, I used tools including Magnet AXIOM and Batbox.

I do not know the countries of origin of these two tools, but they are ISO-certified.

Our office maintained a list from which I came to know that these two tools were ISO-certified.

It is not true that I did not use Magnet AXIOM and Batbox during the examination.

I do not know the percentage of accuracy provided by Magnet AXIOM and Batbox.

For segmentation, I used a tool called Audacity.

I do not know the country of origin of this tool.

I also used Audacity to convert the audio files into .wav format.

It is not true that I did not use Audacity during the examination.

The .wav format is an audio file format. I know its full form, but I cannot recall it at present.

I do not know who developed the .wav format.

Yes, once converted into .wav format, the files can be edited using Adobe Premiere Pro, DaVinci Resolve, and Final Cut Pro.

I have not received any training on Artificial Intelligence (AI).

I have received training on topics including pitch, frequency, and intensity.