The deceased was found slumped across the stainless-steel casing of liquid nitrogen workstation LN-07 in Lab Block C. The workstation is a Linde Kryotechnik KG-200 unit equipped with a Siemens SENTRON PAC3200 integrated safety interlock board. External scene examination revealed no signs of struggle. A single pair of nitrile examination gloves was missing from the box mounted above the workstation (box labelled "BioNexus Labs — Lab Grade PPE — Size M").
| Component | Condition Observed |
|---|---|
| SENTRON PAC3200 safety board | Firmware configuration modified: voltage cutoff threshold raised from 48V to >240V via onboard DIP switch sequence. Factory default configuration requires physical access to sealed internal compartment (accessed via 4-screw panel, T20 Torx). |
| Phase conductor routing | 240V live phase re-routed from internal bus to outer stainless-steel casing of the LN-07 unit via a short (approx. 18cm) bridge conductor. Bridge conductor recovered from inside the panel; appears to be a lab-grade banana plug lead, red insulation, stripped at both ends. |
| Earth bonding conductor | Ground strap connecting casing to building earth — physically disconnected at the casing lug. Disconnection appears deliberate; lug shows fresh tool marks consistent with pliers. |
| Panel cover screws | Three of four T20 screws replaced by hand. Fourth screw cross-threaded and left unseated — internal panel visible from outside if inspected closely. |
| Item | Location | Description |
|---|---|---|
| E01/TM-01 | Left-hand drawer pull of workstation LN-07 base cabinet | Nitrile glove fiber fragments, blue-grey, consistent with BioNexus lab-issue Size M PPE. Three fragments recovered. No fingerprints on the pull itself — consistent with gloved access. |
| E01/TM-02 | SENTRON PAC3200 circuit board surface | No recoverable fingerprints. Surface shows wipe marks consistent with a dry cloth or glove. One partial ridge impression on panel cover (exterior) — insufficient for identification. |
| E01/TM-03 | Bridge conductor (banana plug lead) | Both stripped ends show tool marks consistent with wire strippers. Origin traced to lab general supply — BioNexus Labs stocks this type for instrument calibration. Available in Lab Block C service cupboard (unlocked). |
| Method | Estimate | Basis |
|---|---|---|
| Core–ambient temperature differential | 21:20 – 22:40 (approx.) | Rectal temperature 34.1°C at 00:15; ambient Lab Block C 18°C (air-conditioned). Standard Henssge nomogram calculation, ±45 min confidence. |
| Fixed lividity | Death >2.5 hrs before examination | Hypostasis fixed in position consistent with slump posture across workstation. |
| Victim's last phone activity | 21:52 (text sent) | Metadata recovered from victim's phone. Content: outbound SMS to contact saved as "P.R." — text: "Can we talk? Lab C. Now." Delivered receipt confirmed; no reply received. |
The configuration of the SENTRON safety board firmware is non-intuitive and not documented in the public equipment manual. Knowledge of the DIP switch configuration sequence for override is contained within the Siemens SENTRON Specialist Certification training programme (module SENT-3: Advanced Safety Override Procedures). This is a proprietary training course; HFSL recommends the investigating team obtain a complete list of SENTRON-certified personnel at the facility.
The glove fiber deposits at the drawer pull suggest the modification was carried out by an individual wearing Size M nitrile gloves. BioNexus Labs issues gloves in sizes S, M, and L at each lab block. No gloves matching the fragments were recovered at the scene — suggesting they were removed and disposed of prior to the departure of the responsible individual.