All this week at 6 a.m., 9NEWS is looking at Colorado Cold Cases and where these unsolved murders stand today. You can read the last two stories HERE , HERE and HERE.
For months, Northern Colorado felt a chill.
The series of shootings began April 22, 2015 when someone fired through Cori Romero's car window as she tried merging onto Interstate 25 near Fort Collins. The bullet pierced Romero's neck. Her life was saved by millimeters.
"I was shocked -it took me a while, and sometimes it still doesn't even register what happens," Romero told 9NEWS in 2016.
On the morning of May 18, the shooter's aim was deadly. John Jacoby was gunned down in Windsor. Police believe his case is linked to Romero’s.
Then, on June 3, there were two more shootings -- both in Loveland. One claimed the life of William Connole. Appearing in both cases? A beat-up orange truck.
In September, there was another set of gunfire in Fort Collins. One incident happened at Banner Health, another at Cottonwood Elementary.
"These shootings took place in the public eye if you will," said FBI Supervisory Special Agent Todd Sandstedt. He and Larimer County Sheriff's Office Captain Bob Coleman have spent two years trying to find the person who pulled the trigger.
"There have been person of interest leads popped up," Coleman said. "And to date we've been able to clear all of those persons of interest that came to our attention."
What's making it tough is that each shooting is connected to another, but nothing links all of them.
"I've been in Larimer County since 1988 and this is the first time we've had these characteristics," Coleman said.
Coleman and Sandstedt wonder if the answer lies somewhere in Colorado, or, beyond.
"We have been in contact with authorities from Arizona," Coleman said. "We've been in contact with authorities in California. We've been in contact with authorities in Massachusetts, Michigan."
Dead ends are common. The work is exhausting.
"I think any frustration that comes about during the course of an investigation like this, it's quickly overwhelmed by the sense that we have victims out there and we have families," Sandstedt said.
For now, several agencies are working as a team, and hoping someone out there knows something.
Tips in this case are eligible for up to a $50,000 reward from Metro Denver Crimestoppers.