The Private Investigator's Report Before the Judge: How to Build a Report That Withstands Challenge

It's a scene that repeats in law offices across Spain: the lawyer has the case won on paper, but is missing the fact. The cohabitation they can't prove, the unfair competition they suspect, the fraudulent sick leave everyone talks about and no one can demonstrate.

Private Investigators and Employees on Sick Leave: What a Company Can Legally Investigate

It's one of the questions we hear most from HR departments and labor law firms: ‘We have an employee on sick leave and there are signs they’re carrying out activities incompatible with their condition. Can we hire a private investigator?’

Can Anyone Be a Private Investigator? No: Requirements, Licensing, and Why Impersonating the Profession Also Hurts the Client

Popular imagination can still give the impression that becoming a private investigator is a matter of buying a camera, launching a website, and starting to investigate. In Spain, exactly the opposite is true.

What a Private Investigator Must NOT Do: The Catalog of Evidence That Can Ruin a Winning Case

In the opening entry of this series we explained why a well-built investigator's report has full standing in court. Today we look at the other side: the actions that can turn an investigation into a procedural time bomb.

Recording Without Their Knowledge: When Audio or a Hidden Camera Is Lawful in Private Investigation

Few questions cause as much confusion as this one: can a private investigator record someone without their consent? The correct answer depends on who is recording, where, what is being captured, for what purpose, and what rights are at stake.

The Investigator Undercover: Where Lawful Pretext Ends and Entrapment Begins

One of the first things that surprises anyone who has never worked with private investigators is this: an investigator has no obligation to identify themselves as such to the person under investigation.

Must the Person Under Investigation Be Told? The Duty to Inform, Professional Confidentiality, and Private Investigation

It's a question compliance departments ask us more and more: if the GDPR requires informing people that their data is being processed, how can a private investigator look into someone without telling them?

Asset Investigation Before You Sue: How to Know Whether a €30,000 Lawsuit Is Worth Filing

There's a scene lawyers know all too well. The case is won. The judgment is favorable. The ruling becomes final. Enforcement begins. And then comes the question no one asked at the start: where are the assets?

Deepfakes Before the Judge: How to Challenge —and How to Authenticate— a Video When Any Image Can Be a Lie

For most of the last century, a photograph or a video arrived in a legal proceeding with an extraordinary psychological advantage: if it was recorded, it happened. Generative artificial intelligence has put an end to that comfort.

The Fraudster Pays for the Investigator: Five Lessons From Madrid's High Court on Insurance Fraud

In July 2026, the Civil and Criminal Chamber of Madrid's High Court issued a ruling that deserves close reading by insurers, lawyers, and investigation firms.

The Invisible Variable: Why AI That Predicts Court Rulings May Not See Investigator Evidence

Artificial intelligence has arrived in litigation. Tools now exist that can analyze thousands of rulings, detect patterns, compare precedents, and estimate the probability of certain outcomes.

The Perfect Report: Anatomy of a Document Built to Withstand Challenge

Everything we've explained throughout this series comes down to a single object: the report. The investigator's license. Legitimate interest. The limits. Proportionality. The photographs. The videos. Traceability. The future testimony in court.

OSINT and Social Media: What You Post Reduces Your Privacy, but Doesn't Erase It

‘It's on the internet, so it can be used.’ Few phrases better sum up the legal misunderstanding of our time. Open-source investigation —OSINT— is today one of the most powerful tools in private investigation.

From the Ministerial Order to the AI Act: Forty Years of Legal Evolution in Private Investigation in Spain

Método 3 was founded in 1985. That year, a Spanish private investigator practiced a profession with a long tradition, but one still resting on a regulatory framework far more fragile than today's.

Working While on Sick Leave, Even if Compatible With the Condition: The Second Path to a Fair Dismissal

When we explained how an employee on temporary disability is investigated, we set out one essential rule: it's not enough to photograph someone ‘doing things.’

What the Dani Alves Ruling Lets Us Conclude (on Criminal Evidence, and on Why Investigation in Criminal Proceedings Is Both Possible —and Necessary)

Few recent cases have put Spain's criminal evidentiary system under greater public strain than the Alves case. A conviction by the Barcelona Provincial Court (February 2024, four and a half years in prison); a unanimous acquittal by Catalonia's High Court (March 28, 2025) for insufficient evidence; and, as of today, cassation appeals by the Prosecutor's Office and the private prosecution pending before the Supreme Court, which will have the final word.