"Selling car bomb assemblies online? Sure, grab the buyers asap"
The implication in the article is that the seller was a cop. Posting to a dark web sales portal.
There are of course *other* implications there but I'll bet fairly long odds that this was in the category of that group of LEA that are tasked with "Get some idiot to do something stupid online, and find out where they live". Like the herd of '13 year old teenage girls'.