Blood traces and prisoner calendar uncovered at São Paulo's former DOI‑Codi detention center

A forensic archaeology project led by the Universidade Federal de São Paulo (Unifesp) identified human blood residues in interrogation rooms and an old infirmary of the former DOI‑Codi building, one of Brazil's main torture and detention sites during the military dictatorship. The analysis confirmed hematic material but DNA profiling was impossible because of degradation and successive renovations.

Researchers also uncovered a wall inscription in a third‑floor bathroom that forms a calendar covering 23‑31 October and 1‑4 November 1970. The dating was corroborated by a former political prisoner’s testimony, indicating the calendar was a detainee’s attempt to preserve a sense of time while isolated.

The DOI‑Codi complex in São Paulo’s Rua Tutóia housed more than 7,000 detainees and recorded at least 52 deaths. The study involved specialists from Unifesp, Unicamp, UFMG, UFSC and USP, combining archaeology, architectural analysis and forensic science to document material evidence of the repression era.