More people have reported shots possibly being fired at vehicles along the same stretch of highway where a woman was killed when a bullet penetrated a car door, including one shooting confirmed by authorities Thursday.

Authorities were investigating 10 shootings on or near a stretch of Interstate 270 (search), the highway that circles Columbus, said Franklin County Sheriff's Chief Deputy Steve Martin.

Extra police were sent to patrol the area Thursday.

The first shooting was reported in May and others had come in the past 6 weeks in the area just south of Columbus. Tuesday's killing of Gail Knisley (search), 62, made a total of nine.

Since the killing, Martin said Thursday, several other people have reported that their vehicles may have been hit by bullets along I-270.

Martin said the latest confirmed report involved a woman who got a flat tire Oct. 10 while driving near the interstate. She was told the tire had been shot when she got it replaced, he said. She did not file a report with police.

Martin said authorities don't know yet have any definite physical evidence to show that all the cases are linked and said he is "not ready" to say if the shots have been fired by a sniper.

The sparsely populated area includes woods frequented by hunters and people practicing target shooting, along with industrial sites and some suburban neighborhoods.

Martin would not speculate on the type of weapon used.