The 37 Scientific Evidence of Digital Evidence Tampering on CCTV Footage at Olivier Café: The Jessica Kumala Wongso Case (2016), Carried Out by Muhammad Nuh Al-Azhar and Christopher Hariman Rianto, Who were Under the Leadership of the General Crime Director of the Jakarta Metropolitan Police, Krishna Murti, and the Chief of the Jakarta Metropolitan Police, Tito Karnavian.
EVIDENCE 13: CCTV 3 FOOTAGE WAS DELIBERATELY CONVERTED FROM COLOR TO GRAYSCALE RIGHT WHEN MIRNA SALIHIN ARRIVED AT OLIVIER CAFE AT 17:18 LOCAL TIME
This evidence showed that the CCTV 3 footage was deliberately converted from color to grayscale right when Mirna Salihin arrived at Olivier Cafe at 17:18 local time. Based on the available information, the following was a digital forensic analysis related to this case.
The CCTV 3 video was split into two files: CH03_15.55-17.18.MP4 (color video) and CH03_17.18-18.45.MP4 (grayscale video). This change occurred precisely at the time of Mirna Salihin's arrival, which was very suspicious given the importance of visual information during that period. The video starting at 17:18 local time was converted from color to grayscale, removing color information present in each YUV channel, according to its metadata in the statement by Muhammad Nuh Al-Azhar. This conversion resulted in the loss of crucial color information related to objects, such as the coffee cup and Mirna Salihin's skin tone.
In the Examination Report (BAP) presented by Muhammad Nuh Al-Azhar, the metadata of the CCTV 3 video indicated that the video had a YUV color space, suggesting that the original video was recorded in color format. The presence of the YUV color space in the metadata strengthened the evidence that the video was initially in color before being converted to grayscale.
This loss of visual information had serious forensic implications. For instance, at 17:30 local time, Devi Siagian carried the coffee cup from table 54 to the cocktail bar. The color information of the coffee cup could have indicated any color changes allegedly caused by hazardous substances like cyanide. Additionally, at 17:28 local time, Mirna was taken out of the cafe in a wheelchair. The color of Mirna's face and arms could have provided clues about her physical condition, such as signs of poisoning or allergic reactions.
This color manipulation destroyed the video's credibility as evidence, suggesting an attempt to conceal important information. This action was carried out by Muhammad Nuh Al-Azhar and Christopher Hariman Rianto, who should have been responsible for maintaining the integrity of every bit of information in the video. This manipulation showed a serious breach of professional ethics and raised doubts about their analytical results in this case.
The manipulation of the CCTV 3 footage was a very critical act. The removal of color information from the video was highly detrimental because such information was essential for analyzing the volume and color of the coffee as well
