Witness 2: Atikur Rahman
Evidence given by Atikur Rahman
My name is Atikur Rahman, aged 34 years, son of [redacted]. My address is [redacted] Mymensingh. I am serving as a Sub-Inspector of Police at IT Forensic, CID, Bangladesh Police, Dhaka.
On 07.10.2025, I received two exhibits from the Investigation Agency of ICT under Complaint Register No. 130 dated 06.10.2024 through the Investigating Officer:
Exhibit-1: A Twin MOS 64GB pen drive containing four disputed audio recordings with five voices.
Exhibit-2: A Verbatim DVD-R (4.7 GB) containing sample voices of Salman F. Rahman, Zunaid Ahmed Palak, Anisul Huque, Dr. Shirin Sharmin Chaudhury, and Sheikh Rehana.
As per instructions of the superior authority, I commenced examination on 08.10.2025.
The task assigned by the Investigating Officer was to determine whether the voices in Exhibit-1 matched the sample voices in Exhibit-2.
Upon examination, I opined as follows:
The male voice in Exhibit-1 matches with the sample voice of Anisul Huque in Exhibit-2.
The male voice in Exhibit-1 matches with the sample voice of Zunaid Ahmed Palak in Exhibit-2.
The male voice in Exhibit-1 matches with the sample voice of Salman F. Rahman in Exhibit-2.
The female voice in Exhibit-1 matches with the sample voice of Sheikh Rehana in Exhibit-2.
The female voice in Exhibit-1 matches with the sample voice of Dr. Shirin Sharmin Chaudhury in Exhibit-2.
After completion of the examination, I submitted my report (Exhibit-8), which is included in the seizure list and documentary evidence (pages 219–220), bearing my signature (Exhibit-8/1).
I also annexed 23 pages with the report, which are included at pages 221–243.
This is my deposition.
Cross Examination on behalf of Zunayid Ahmed Polok.
Defence: You and your superior officer are under the Ministry of Home Affairs?
PW: I am; I do not know whether the Investigating Officer is.
Defence: Are you aware that each pen drive has a unique identification number?
PW: A pen drive does not necessarily have a unique identification number externally; however, unique identifiers may exist in its properties.
Defence: Did you mention the identification number in section 2.1 of your report?
PW: No, I did not mention it there; however, hash values are mentioned in the annexure.
Defence: How many audio files did you receive?
PW: I mentioned in my report that I received four audio files and five sample voices.
Defence: Did Palak mention a “complete shutdown” in the audio you examined?
Prosecution raised an objection on the ground that this question is irrelevant; here the issue is voice matching, not the content.
Tribunal: Objection sustained.
Defence: Did you review the forwarding letter of the Investigation Agency?
PW: I saw the letter dated 27.09.2025 but did not review it.
Defence: Do you know when and from which channel the sample voices were collected?
PW: No, I do not know.
Defence: Can you say from which device the data was transferred to the pen drive?
PW: No, I cannot say from which device the data was transferred to the pen drive.
Defence: Did you compare whether the disputed voices match specific individuals?
PW: The Investigating Officer did not request identification of specific individuals.
Defence: You did not provide a specific opinion regarding similarity or dissimilarity.
PW: The statements of voices were not included in section 5.2 of the report.
Defence: You intentionally omitted the voice statements.
PW: It is not true that I intentionally omitted the voice statements.
Defence: Did you prepare transcripts of the voices?
PW: No, I did not.
Defence: Did you describe pitch, tone, rhythm, frequency, or articulation?
PW: Not in the report, although such analyses were conducted.
Defence: Did you segment the audio into specific time frames?
PW: Yes, but I do not recall the duration.
Defence: Did you use Pyannote audio tools?
PW: No, but I used other recognized tools.
Defence: Did you create voice prints?
PW: Yes, but it was not mentioned in the report.
Defence: Did you use any deep learning model?
PW: No.
Defence: Did you use clustering and identification methods?
PW: No.
Defence: Did you convert the audio to 16 kHz mono channel?
PW: Not specifically to 16 kHz; however, I converted to mono channel and used various sampling rates.
Defence: Do you know the source of the voices?
PW: No.
Defence: Your opinion is flawed.
PW: It is not true that my opinion is flawed.
Defence: The report was prepared under instruction of the investigation agency.
PW: It is not true that the report was prepared under instruction of the investigation agency.
Defence: You did not use internationally recognized voice analysis software.
PW: It is not true that I did not use internationally recognized voice analysis software.
Cross-examination on behalf of Sajeeb Ahmed Wajed Joy
Previous Cross-examination was adopted
Defence: How long did it take to prepare the report?
PW: 22 days.
Defence: When did you receive the exhibits?
PW: On 08.10.2025 I received the exhibits.
Defence: Who supervised your examination?
PW: Additional Superintendent of Police (Forensic) and Superintendent of Police (Forensic).
Defence: Did you take approval of your supervisor before the submission of the report.
PW: Approval was taken before submission, though not mentioned in the report.
Defence: Your report is not related to this case.
PW: It is not true that the report is not related to this case.
Next date: 12.04.2026