narcling
n.— «“It’s rough stuff,” said John Donnelly, a lead instructor at the DEA training facility on the sprawling Marine base at Quantico. Donnelly got his start in the late 1980s busting meth labs in California’s Central Valley as a new DEA agent, or “narcling,” as he called it.» —“How to raid a meth lab” by Les Blumenthal Bellingham Herald (Washington) Feb. 18, 2007. (source: Double-Tongued Dictionary)
There is an English slang word ‘nark’ meaning ‘snitch’ or someone who gives away information. It comes from the Romany (gypsy) word ‘nak’ meaning nose. presumably then someone who is nosey?