A man and his daughter were driving down a rural highway in Anderson County, South Carolina, on January 30, 2018, when they noticed something odd—a glowing wicker basket in the middle of the road. The man stopped to examine the package. It exploded, causing minor burns to his leg.

Among the bomb remnants police found at the scene was a piece of paper with Arabic writing referencing Osama bin Laden, leading investigators toward a possible terrorism motive. Local, state, and federal law enforcement collected evidence and sent the bomb components to the FBI Laboratory in Quantico, Virginia, where experts looked for fingerprints, DNA, and other clues. The Laboratory’s experts provided on-scene investigators with a steady stream of actionable leads and information based on their findings.

The next day, after word of the incident got out, another resident called the Anderson County Sheriff’s Office to report he had seen a similar-looking device days earlier on a nearby bridge. He did not call police at the time, but he had taken photos of it with his cell phone. On February 4, another bomb-like object was found, placed in a black box with a letter that pledged allegiance to the Islamic State and said the community was no longer safe.

Police and the FBI then stepped up an already fast-moving investigation of what was now clearly a serial bomber.

“Every time we responded to a scene, we immediately provided evidence to the FBI Laboratory for analysis,” said Special Agent Tanya Evanina, who worked the case as part of the FBI Columbia Field Office’s Joint Terrorism Task Force (JTTF). “We also worked with local law enforcement to canvass the area, looking at surveillance footage and talking with local businesses about the component parts.”

As investigators hunted down leads, more than 10 days went by without another incident—but the bomber wasn’t finished. On February 15, another device was found, hidden inside a teddy bear. The teddy bear was left in a basket in the middle of the road.

“This was deliberately placed where a child or passerby could have found it. Fortunately, someone saw it and knew to call us,” said Special Agent Christopher Derrickson, a supervisor in the FBI Columbia JTTF.