Editor's note: In this special three-part series exclusive to ThisWeek Community News, retired FBI special agent Harry Trombitas chronicles his experience as a lead investigator into the fatal shooting that occurred November 2003 on the south corridor of Interstate 270 in Franklin County.

Editor's note: In this special three-part series exclusive to ThisWeek Community News, retired FBI special agent Harry Trombitas chronicles his experience as a lead investigator into the fatal shooting that occurred November 2003 on the south corridor of Interstate 270 in Franklin County.

It was a sunny, brisk morning Tuesday, Nov. 25, 2003, when two best friends set off for Columbus from Washington Court House for a day of shopping, catching up with news of each other's families and enjoying their time together.

As Mary Cox drove her white Pontiac Grand Am eastbound on Interstate 270 on south of Columbus, heading toward Easton Town Center, neither she nor her passenger, 62-year-old Gail Knisley, had any idea their lives would be changed forever.

As the Grand Am approached the state Route 23 Circleville exit at approximately 9:57 a.m., the women heard a loud bang, similar to a balloon popping.

Knisley suddenly slumped over in the passenger seat and Cox realized her friend had been shot. She pulled the vehicle to the right side of the highway, grabbed her cellphone and dialed 911.

The 911 operator calmed Cox down and instructed her how to comfort Knisley. Cox hadn't noticed the bullet that had entered the driver's side door, passing across the front seat and narrowly missing her, before striking Knisley in the side of the chest.

The bullet continued its path of destruction inside Knisley, eventually severing her aorta. By the time medical personnel transported Knisley to the hospital, she had bled out and died.

Chief Deputy Steve Martin of the Franklin County sheriff's office and other investigators responded to the scene. Had the shooting occurred a hundred yards away, the investigative jurisdiction would have fallen to the Columbus Division of Police.

Martin headed back to his office where he would spend most of the next 120 days leading the investigation, working through Thanksgiving, Christmas and New Year's Day, taking time off only to sleep and eat.

While he drove, Martin ran the possible scenarios through his head. Was Knisley or Cox the intended target? Or were they merely victims of a random act of violence? In either case, shooting at two women in their 60s driving on I-270 in broad daylight made no sense.

Columbus is known for a lot of things: a fairly large city with a small-town feel; weather patterns that change daily, usually from bad to worse; the Ohio State University; and the home of such businesses as White Castle, Wendy's and The Limited.

But it is also known for the strong bonds between area law-enforcement agencies at the local, state and federal levels.

Almost immediately, the Franklin County sheriff's office was joined by the Columbus Division of Police; the Bureau of Alcohol, Tobacco and Firearms; the Ohio State Highway Patrol; and the FBI, all wanting to lend manpower and resources. As a result, a task force was established with daily participation by these agencies.

Before the investigation would be completed, just about every law-enforcement agency in central Ohio would contribute. This case became one of the most significant investigations ever conducted in central Ohio.

At the time of the shooting, I had been an FBI agent for about 19 years, having worked in field offices in Omaha, Neb., St. Louis and New York City before my transfer to Columbus in 1991.

I had worked mostly violent crime cases, including serial murder, single homicide, kidnapping, bank robbery, extortion, threats, property crime and even a little terrorism and foreign counter-intelligence.

My supervisor assigned me as the case agent, and I proceeded to the sheriff's office, where I would spend the next four months working with Martin. We hit it off immediately and became good friends during the investigation.

As investigators began to examine the Knisley homicide, we learned the bullet recovered from Knisley's body was a 9 mm round. Exhaustive interviews were conducted with Cox and Knisley family members and friends to determine if Knisley or Cox could have been targeted. Based on the trajectory the bullet took that pierced the Grand Am and struck Knisley, it had to have been fired from ground level or perhaps a moving vehicle.

This was no accident. It seemed as though the shooter had no care or concern where the bullet went after it left his or her gun, since it was clear that Cox could have been the victim just as easily as Knisley. Despite the fact that the shooting took place in daylight hours on a heavily traveled roadway, no eyewitness came forward with any helpful information.

One of the first steps taken by task force investigators was an attempt to identify other possible shooting incidents that could be linked to the Knisley homicide.

No shooting victims could be located, but plenty of shooting incidents could. Investigators began to uncover numerous cases prior to the Knisley homicide in which vehicles and buildings had been shot along the I-270 south corridor.

Because the incidents had occurred in several different jurisdictions and were labeled on various reports with different criminal violation terminology, no one realized one person could be responsible.

Investigators identified 10 linked incidents in the months preceding the Knisley homicide. Clearly, a serial shooter was operating in southern Franklin County, and it was but for the grace of God that we didn't have more victims.

Despite the publicity the case received and the efforts of the task force, the shooting incidents continued. As more were linked, Columbus went into a panic, particularly those working, eating or traveling near the I-270 south corridor.

The level of panic was heightened by a recent trial for several sniper-style killings near our nation's capital.

Over the course of three weeks in October 2002, John Allen Muhammad and Lee Boyd Malvo shot and killed 10 people and critically injured three others in Maryland, Virginia and Washington, D.C. The investigation was dubbed the "D.C. Sniper Case."

Muhammad and Malvo were arrested Oct. 24, 2002. In September 2003, Muhammad was sentenced to death. In October 2003, Malvo was sentenced to six consecutive life sentences. In November 2003, Gail Knisley was killed by an apparent copycat. No wonder everyone in central Ohio was on edge.

Next week: Quelling resident fears and developing a profile of the shooter.

The opinions expressed in this article solely are those of the author, Harry Trombitas, and not those of the FBI or any other agency. Retired Special Agent Trombitas writes the Case in point column for ThisWeek Community News. He currently is system vice president of security operations for OhioHealth and a senior consultant for Armada, a security consulting company, in Powell.