An Irish American police officer found an extensive marijuana farm during a routine helicopter flight outside of Chicago on Tuesday. He is now being hailed by Chicago police as busting one of the biggest drug operations in the city’s recent history.

The Chicago Tribune reports on the massive find that was first noticed by tactical flight officer Ed Graney. During a routine helicopter ride, Graney noticed bright green plants that were arranged in neat rows growing amongst the dark green foliage.

"I told (my partner), 'Turn around, let's go check this out, make sure we have what we have here,'” said Graney, instantly suspicious that the plants were marijuana.

Graney and his partner took photographs of the plants and shared them with their supervisor, who then shared them with a narcotics team.

On Wednesday, Graney and the helicopter’s pilot Officer Stanley Kuprianczyk were praised as busting the largest outdoor marijuana operation in recent Chicago history.

Nick Roti, chief of the Police Department’s bureau of organized crime, praised Graney’s actions in a press conference: “If it wasn’t for the helicopter unit, we would have never found it.”

The site is well hidden by foliage and though it’s closer to a freeway, tall grasses would have prevented any motorists from noticing the site. Found at the site were sleeping bags and food, leading officers to believe that someone was camping out there. The plants were within harvest period.

Chicago isn’t known to have a climate that will nurture the growth of marijuana plants, thus making the find that much more unexpected.

"Usually you see marijuana plants that are 3 feet high, 4 feet high, (but) these resemble plants you see out in California," Roti said of the 6-foot plants that were discovered.

Police Superintendent Garry McCarthy said that the narcotics unit is not only dedicated to stopping drug sales, but also to halting the violence that so often comes along with it. 

"People will do whatever they can to make their money,” said McCarthy. “I think that spending that much time and effort setting up an operation like this in a place like Chicago, it is brazen."

Following the criminal discovery, police officers, along with crews from the city's forestry and streets and sanitation departments, spent Wednesday cutting down the plants, which will be burned. Weed-killer is also being spread on the area to ensure that there is no regrowth of the marijuana plants.

As of Wednesday, no one was in custody in relation to the marijuana farm. Police are investigating who owns the land.

Massive marijuana farm found outside ChicagoHeather Charles / Chicago Tribune