If you’re a nerd for random car trivia, don’t let anyone tell you your hobby is useless. A Redditor proved just how useful niche automotive knowledge can be when they helped solve a mysterious hit-and-run with just a picture of a small piece of broken plastic.

Tragedy struck in Washington State when a 63-year-old woman was found dead by the roadside. Her bicycle was abandoned nearby. The mid-morning accident occurred on a straight stretch of a state road 60 miles south of Seattle.

Whoever struck and killed the bicyclist drove away. Police detectives had the mangled bicycle, the body, and a single piece of plastic trim. With no other options, they posted a picture of the trim online.

Reddit weighs in

Reddit users cross-posted the photo to the /w/WhatIsThisThing forum. Users who frequented forums such as /r/Cars and /r/Autos all tried to narrow down the make and model of the vehicle. Then a Redditor named Jeff who was watching football happened to open the website. He immediately recognized the piece of plastic.

Jeff had once worked as a vehicle inspector in Maryland. A “mandatory headlamp adjustment” was part of his checklist. He recognized the plastic headlight trim from a 1980s Chevrolet C/K pickup instantly.

Later, Jeff admitted that at first identifying the car part was a purely intellectual challenge. He posted a comment and went back to his football game. But the detectives used Jeff’s tip to arrest Jeremy Simon, the driver of the 1986 Chevrolet K-10 that had hit the woman.

Jeff said, “It wasn’t until I read a private message from a friend of a friend of the deceased explaining how distraught the family was and thanking me for my help that [I realized] what I had just done was very real…Someone was dead and [the perpetrator] may have gotten away with it, except for the randomness of the person that posted the link and me being online at nearly the same moment.” You can learn more about the incident in the video embedded below: