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The Evidence Question Weekly

No. 2 · 16 October 2026

When the *witness* is the suspect: AI logs nobody can trust

A structural problem at the heart of agentic AI, and what courts are doing about deepfakes.

Our take

The log that writes itself

Say you're investigating an incident. You ask the suspect what happened, and they hand you a diary they wrote themselves. Would you trust it?

That's the problem with AI audit logs. When an AI agent acts on its own, the system being audited is also the one keeping the record. If it malfunctions or gets compromised, it can falsify its own logs. The witness is the suspect.

Courts are starting to notice. A tribunal in British Columbia rejected AI-generated exhibits because they didn't authentically represent the people they claimed to depict. Judges in the US are tightening authentication rules for deepfakes and AI-generated evidence. The message is clear: you can't always tell, so prove it.

The answer isn't more AI watching the first AI. It's separating the log from the thing being logged, so a change shows even when it's made by someone with the right access.

For the coffee break: An AI agent that writes its own audit log is like a suspect keeping their own diary.

The Witnium team

The week in 30 seconds

  • When AI agents write their own logs, the witness is the suspect.
  • Courts are rejecting AI evidence that can't be authenticated.
  • Sweden's financial regulator is examining how banks defend against AI attacks.

What happened

Evidence · Opinion

The witness was the suspect: why AI audit logs can't be trusted

When an AI agent acts and also writes its own audit trail, you have a structural problem: the thing you're checking is keeping the record. A malfunctioning or compromised AI could falsify its own logs. That's not evidence, it's a conflict of interest.

Why it matters for evidence: The AI Act requires logging, but if the system can edit what it logs, the record won't hold up when challenged.

Source: daily.dev

Cases · Court

When the evidence is the question: AI authentication in the courtroom

A court rejected AI-generated exhibits after finding they did not authentically capture the speech or image of the person they purported to depict. The case shows how courts assess the reliability of AI evidence under free evaluation of evidence principles.

Why it matters for evidence: When AI-generated material is challenged, the burden is on the side presenting it to show it's authentic.

Sources: digitalmountain.com, stangelawfirm.com

Rules · Sweden

FI examines how Swedish banks defend against AI-powered attacks

Finansinspektionen will examine how Swedish banks, insurance companies and financial infrastructure firms are preparing their defences against AI-powered cyberattacks. The review is conducted under DORA, which sets requirements for digital operational resilience including protection of logging systems.

Source: breakit.se

How it works · Guide

How do you audit what an AI agent did?

Vercel publishes a technical guide on building audit trails for AI agents that connect identity, tool calls, approvals and results to enable reconstruction of agent actions and investigation of errors. The article provides practical implementation patterns for logging and tracing autonomous AI system behaviour.

Source: vercel.com

Where a digital witness fits

What an *AI agent* did, and on whose instruction

Say an AI agent changes a customer's order or files a report on its own, and the customer says nobody asked it to. The question becomes: can you show what the agent did, when it did it and who instructed it?

A digital witness seals each instruction, tool call and result as the agent acts. The agent's actions are logged separately from the agent itself, so a change shows even if the agent or someone with admin rights tries to rewrite the record.

Anyone you share the log with can check the fingerprint against the sealed one. If they match, nothing has changed since sealing. Change a single character and they won't match.

How it would work

  1. 01Your system sends a fingerprint of each agent action to WitniumChain through the MCP server, the SDK or the REST API, and gets a witness ID back.
  2. 02When something is questioned, you calculate the fingerprint of the log again.
  3. 03If it matches the sealed one, the record is unchanged. If not, something has been altered.

Give your agents receipts

Seal agent actions through the MCP server. The first 2,000 witnesses a month are free.

The evidence clock

More rules, more records.

Step chart of the requirements we track that call for logs, records or evidence. 14 of 26 apply today, rising to 26 by 2 August 2028.

14 of the 26 requirements we track apply today. 12 more arrive by 2 August 2028.

Next up

Each step is a requirement in our regulation bank, linked to its primary source.

From the newsroom

Seal pending.

News · The Evidence Question Weekly