Over 200 law enforcement officials in Missouri embarked Wednesday on an intensive new search for a teen girl last seen nearly three years ago -- but by the end of the day, authorities still were left without a break in the case.

Kara Kopetsky, 17, vanished early in May 2007 from her hometown of Belton, Mo. The FBI downplayed speculation that there were new leads in the case, as authorities said they wanted to take advantage of ground conditions to go over an area that had been searched before, Fox4KC.com reports.

Missouri Police from Kansas City, Belton and Cass County, as well as the FBI and a number of United States Marines, participated in the search of a 400-acre wooded area near the former Richards-Gebaur airport.

FBI spokeswoman Bridget Patton said the area had been searched before, but "never a shoulder-to-shoulder grid search," KansasCity.com reports.

"We had this information, but based upon the weather right now, the foliage is dead, there's no snow on the ground, the actually weather, the environment, leads to a more thorough search at this point," Patton told Fox4KC.com.

Kopetsky's last confirmed sighting was at her high school, but there were also reports that she was spotted two days later at an area gas station in Lewisburg, Mo., on the same day her cell phone and debit card were last used.

The teen's mother, Rhonda Beckford, said her daughter had called that morning to ask her to bring her history textbook to school and wash her work uniform, but she never arrived at work that afternoon.

In June 2007, Missouri police released a surveillance video in hopes it would offer clues about the teenage girl's disappearance. The video showed Kopetsky at her high school the morning of May 2, 2007, the last time she was seen.

Kopetsky disappeared about six miles from where 18-year-old Kelsey Smith's body was found. Smith was abducted from Overland Park, Ill. Edwin R. Hall, 26, was sentenced to life in prison without parole for her kidnapping, rape and murder.

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The Associated Press contributed to this report.