What screenshots, exports, certified captures, notarial records (ata notarial) and forensic extraction prove, how a conversation is forged and how forensic examination tells the authentic from the fabricated.
A screenshot is a photograph of a screen. It does not carry the app's internal records, nor does it show which device it came from. With two phones, anyone can put together a convincing conversation in a few minutes.
Certified captures and notarial records do a better job of recording what the screen showed, but they do not say whether the conversation existed as it appears. Once a printed message is challenged, the CPC (Brazilian Code of Civil Procedure) requires the electronic authentication to be produced or an expert examination to be carried out (CPC, art. 422, § 1º and § 3º). And the STJ (Brazilian Superior Court of Justice) has been ordering expert examination where there is reasonable doubt about integrity.
With a live demonstration and cases from the laboratory, Adriano Vallim, Forensic Expert and Digital Crime Specialist, shows what each form of evidence supports and how forensic examination tells the authentic from the fabricated.
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A candidate filed PDFs in electoral proceedings with screenshots of alleged group conversations. The examination reproduced the screens in minutes, with ordinary devices. The screenshots carried the traces of their fabrication, and the report declared the fraud.
A retailer was claiming card sales that, he said, had not been credited, and filed more than a dozen receipts on thermal paper. The examination queried the authoriser's database and recorded the procedure in a notarial record: all of them were forged.
A company receives screenshots of an employee's conversations, captured by a colleague on a computer where the WhatsApp Web session had been left open. Whoever has the session can send and delete messages in the account holder's name. The evidence is born from access without legitimacy and from manipulation that cannot be ruled out.
Each group of three receives four screenshots made for the class, with fictitious names: some authentic, others fabricated. In 15 minutes, using the checklist in the materials, the group decides, screenshot by screenshot, what the image allows one to state, which signs appear and what to request. The instructor then reveals how each screenshot was made.
Laws and rulings discussed
CPC, art. 384 (Brazilian Code of Civil Procedure) · CPC, art. 422, caput, § 1º and § 3º · STJ (Brazilian Superior Court of Justice), RHC 99,735/SC, 6th Panel, decided 27 November 2018, headnote cited in AgRg in RHC 133,430/PE · STJ, AgRg in RHC 133,430/PE, 6th Panel, news release of 9 March 2021 · STJ, AgRg in HC 828,054/RN, 5th Panel, decided 23 April 2024, Case Law Bulletin 811 · STJ, AgRg in HC 943,895/PR, 5th Panel, decided 3 September 2025, published in the DJEN on 8 September 2025 · STJ, AgRg in AREsp 2,967,267/SC, 5th Panel, decided 21 October 2025, Case Law Bulletin 869 · STJ, AgRg in HC 1,014,212/ES, 6th Panel, decided 10 February 2026, Case Law Bulletin 878 · STJ, HC 1,054,038/SP, 6th Panel, decided 10 March 2026, Case Law Bulletin Special Edition 33 · STJ, Inq 1,674/DF, Special Court, decided 6 May 2026, Case Law Bulletin 891 · STJ, news release of 3 June 2026, Jurisprudência em Teses, issue 281
See also
WhatsApp and Chat Examination → Forensic Extraction from Mobile Phones and Devices → Digital Questioned Document Examination → For Lawyers → See all courses →