COLUMBUS (AP) - A car shot in the hood this month was linked Wednesday to a series of highway shootings that have targeted cars, school buses and buildings.

The total number of related shootings on or near a stretch of Interstate 270 increased to 19, Franklin County Chief Sheriff's Deputy Steve Martin said. One of the shootings in November killed a woman who was on her way to a doctor's appointment.

A driver on I-270, which encircles the city, reported that the bullet hit the hood Sunday, then struck and cracked the windshield. The driver wasn't hurt.

Martin said investigators found only bullet fragments and could not immediately link the latest shooting ballistically to seven other cases. Investigators still are analyzing the fragments and inspecting the area, Martin said.

The serial shootings along I-270 started in May, although most have occurred since October.

The last shootings linked to the case nearly a month ago were bullet marks found on two school buses from a district near the highway.

The latest shooting was added to the investigation because of its proximity to others and because bullet fragments were found in the hood, Martin said.

The driver was a young man who was going home at 2:15 a.m. when his car was struck, Martin said. He would not identify the driver at the request of Columbus police. The driver pulled over immediately and called Columbus police on his cell phone, he said.

The driver remembered seeing other vehicles nearby when his car was struck, Martin said.

''We believe there are citizens out there who were traveling throughout the area during the time of this shooting incident who may have seen a suspicious person or vehicle,'' Martin said.

He said he could not comment on where the shots may have been fired from.

About 3,430 tips have been called in, and investigators are looking into about 200 people named in calls, Martin said. Investigators daily add and subtract suspects from their list as they rule them out or receive calls naming new people, he said.

No one has called claiming credit for the shootings, Martin said.

Gail Knisley, 62, died in a shooting Nov. 25. No one else has been injured.

Investigators have been trying to find the owners of two vehicles that stopped at a gas station around the time of a shooting at a house Dec. 15. Investigators say they want to know if they heard or saw anything suspicious at the station near the home.

The drivers of two other vehicles pictured in security camera shots released by investigators have contacted police and were ruled out as suspects, Martin said.

A $60,000 reward from local businesses is being offered.