Post-transaction investigations: John Matas on fraud attacks and working with law enforcement
Today we are talking about post-transaction investigations and why they matter so much more when fraud attacks are increasing across both online and in-store environments.
I sat down with John Matas, Head of Global Fraud and Risk Operations at Etsy, for part one of a really thoughtful conversation about what he has seen shift in fraud over the last few years. We talk about his move from a traditional retailer into a growing two-sided marketplace, what that transition revealed about marketplace fraud operations, why fraud losses seem to have increased so dramatically, and what fraud teams need to understand about investigations and working with law enforcement.
John brings the kind of perspective I always appreciate because it is grounded in real operations. He has seen fraud from multiple sides, understands both retail and marketplace environments, and knows that strong fraud strategy is not just about prevention at the top of the funnel. It is also about what happens after the transaction, how cases are built, and what teams can learn when they investigate what already got through.
And that matters.
Because post-transaction investigations are not just about looking backward. They can surface fraud attack patterns, improve fraud case development, strengthen future controls, and sometimes help support the prosecution of bad actors. That is especially important when fraud is getting more coordinated, more expensive, and harder to ignore.
What you’ll hear in this episode:
- What John noticed when transitioning from traditional retail into two-sided marketplace fraud
- Why fraud attack increase and fraud loss trends have become more severe in recent years
- How post-transaction investigations can improve fraud prevention investigations and case development
- What the benefits and risks are when teams rely more heavily on post-purchase fraud analysis
- Why working with law enforcement can matter when prosecuting bad actors across retail and marketplace fraud
You should listen to this episode if you:
- Lead fraud, risk, or trust and safety teams and want a stronger view of post-transaction investigations
- Work in marketplace fraud operations or two-sided marketplace fraud and need practical insight
- Care about fraud investigations, fraud case development, and organized retail fraud trends
- Want to understand the challenges of working with law enforcement on fraud cases
- Need better context for fraud loss trends and the growing complexity of fraud attacks
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Episode notes & key takeaways
Why post-transaction investigations still matter in modern fraud programs
Let’s break this down.
Fraud teams spend a lot of energy trying to stop bad activity before it happens, and that absolutely makes sense. But one of the strongest reminders in this conversation is that post-transaction investigations still play a critical role in strong fraud programs. They help teams understand what got through, why it got through, and what signals may have been missed in the moment.
That is where post-transaction investigations become much more than cleanup work. They create a learning loop. They help teams improve fraud prevention investigations, identify new attack methods, and build better fraud case development over time. If a team never looks back deeply enough, it becomes a lot harder to spot patterns that could help prevent the next wave.
Here is what is actually changing:
- Post-transaction investigations help teams learn from fraud that was not stopped upfront
- Fraud investigations can reveal patterns that improve future controls and decisioning
- Post-purchase fraud analysis creates stronger feedback loops for fraud teams
- Fraud case development gets better when teams study both successful and failed attacks
Why marketplace fraud operations require a different lens
Here’s what’s actually happening.
John talks about the adjustments he noticed moving from a traditional retailer into Etsy’s environment, and that part is especially useful. Two-sided marketplace fraud is not just retail fraud with a different label. The dynamics are different because the platform has to think about trust, abuse, payments, and risk across multiple participants at once.
That changes how fraud teams operate. Marketplace fraud operations often require a broader view of behavior, incentives, and customer interaction than more traditional models. It also means fraud teams may need to think differently about what risk looks like, how fraud loss trends show up, and what kind of investigations actually help reveal the bigger picture.
- Two-sided marketplace fraud introduces different risk dynamics than traditional retail
- Marketplace fraud operations often require broader context across multiple user types
- Etsy fraud strategy reflects the added complexity of platform-based trust and risk
- Fraud teams need different investigative instincts when the business model changes
Why fraud attacks and losses have increased so dramatically
One of the big questions in this episode is why fraud and losses seem to have gone up so much over the last few years. John shares his perspective on the contributing factors, and it lines up with what a lot of fraud fighters have been seeing. Fraudsters have more tools, more access, more organization, and in many cases, more ways to monetize quickly than they did before.
That increase is not always just about one new tactic. It is often about a combination of conditions that make fraud more scalable and more profitable. That is why fraud attack increase and fraud loss trends have become such important business issues. Companies are not just dealing with more fraud. They are dealing with more adaptive fraud, more coordinated fraud, and more pressure to respond faster than before.
- Fraud attack increase is often tied to scale, coordination, and better criminal tooling
- Fraud loss trends reflect deeper structural shifts, not just isolated incidents
- Organized retail fraud and online fraud are both becoming more operationally complex
- Teams need stronger investigations to understand why certain attack patterns are growing
Why working with law enforcement is valuable and difficult
This is another part of the conversation I really appreciated. Fraud teams often want to prosecute bad actors, but the reality of working with law enforcement can be much more challenging than people expect. Cases need to be built well. Evidence needs to be organized. Priorities need to align. And not every fraud event will get the attention teams hope it will.
That does not mean the effort is wasted. It means fraud teams need to understand both the benefits and the limitations of working with law enforcement. The stronger the fraud case development, the better the chance a team has of supporting meaningful action. But it also helps to be realistic about what law enforcement fraud cases require and where internal investigations can still provide value even when prosecution is uncertain.
- Working with law enforcement requires strong documentation and clear fraud case development
- Law enforcement fraud cases often depend on scale, evidence quality, and investigative readiness
- Prosecuting bad actors can be difficult, but stronger cases improve the odds
- Fraud prevention investigations still create value even when external action is limited
The big takeaway from this episode is pretty simple. Post-transaction investigations are not secondary work. They are part of how strong fraud teams learn, adapt, and build better long-term strategy. John Matas brings a practical perspective on rising fraud trends, the realities of marketplace risk, and what it actually takes to investigate cases and work with law enforcement in a meaningful way. That is exactly why this conversation is worth your time.
