✅ What the “cazadores de pedófilos” do

Some volunteer groups in Spain infiltrate chats or social-media groups posing as minors, in an attempt to expose adults who seek to exploit children online. For example: a report described a young informatics student in Asturias who, working with around 30 people, used Telegram chats to identify users exchanging child-pornography material. lne.es+2El País+2
On a broader European level: volunteers adopt fake-profiles of minors to lure suspected offenders, gather evidence (chat logs, etc.) and sometimes even confront suspects in person. La República+1
They monitor forums, file-sharing networks (P2P), and messaging platforms for signs of grooming and distribution of child sexual abuse material (CSAM). infobae+1

⚠️ Legal, ethical and practical issues

Undertaking impersonation of minors or inducing suspected offenders can raise entrapment, evidence admissibility, and due-process concerns. For instance, one article explained:“La ola de ‘cazadores de pedófilos’… algunos ‘hacen pasar’ por niños en internet para citar a posibles violadores y ‘castigarlos’ violentamente…” elimparcial.com
Publication of videos or public shaming before legal process may infringe rights of presumed innocence, privacy, and may even endanger official investigations. elimparcial.com
The legality of amateur vigilantism in Spain is doubtful: for example, in a Reddit discussion someone pointed out that publicising videos of “catching pedophiles” can lead to legal consequences depending on how the footage is obtained and shared. Reddit
The risk of misidentification, vigilantism going rogue, or disrupting investigations is non-trivial.

There are documented cases of “hunters” or self-organised citizen groups in Spain operating (somewhat) informally. e.g., the Asturias example: “El joven informático asturiano que caza pederastas en internet” from 2016. lne.es
There is no strong evidence of large formal national-organised “cazadores de pedófilos” with official sanction; most are volunteer, local, informal.
Official police/cybercrime units still lead major operations against child-exploitation, e.g., the reported stats about the 2023 investigation into cyber-sexual crimes against minors. infobae