By Anita Chang
The Associated Press

COLUMBUS - Authorities closed nearly half of the beltway around the city Saturday as federal authorities investigating 14 shootings there used lasers to take ballistic measurements.

Agents from the Bureau of Alcohol, Tobacco and Firearms walked in the westbound lane of Interstate 270, as a white sedan crept along in the eastbound lane.

The car appeared to be similar to the one 62-year-old Gail Knisley was riding in when she was fatally shot on 270 on Nov. 25.

A red laser beam could be seen shining between the driver's side door and agents working along the opposite side of the highway.

The car stopped often and occasionally backed up as investigators with flashlights searched wooded areas and brush along the highway.

Franklin County Chief Deputy Steve Martin said the measurements would be concentrated on a 4-mile stretch of road between State Route 622 and U.S. 23, although Ohio Department of Transportation Michelle May said the agency was closing 23 miles of highway from 5 to 7 p.m. between the two places where Interstate 70 intersects with the 270 outerbelt.

Martin wouldn't comment on whether authorities also were using the time to install security cameras along the highway.

Also on Saturday, 40 investigators went door to door to talk to residents near a school that was the site of one of the shootings, Martin said.

The shootings around a 7-mile stretch of I-270 began in May but have happened mainly in the past two months.