-- Police on Wednesday arrested a man in the abduction and death of a teenager who disappeared four days ago from a store parking lot.

Authorities said 18-year-old Kelsey Smith's body was found across the state line at a lake in Grandview, Missouri.

Overland Park Police Chief John Douglass identified the suspect as Edwin R. Hall, 26, of Olathe. He was expected to be charged Thursday with premeditated first-degree murder and aggravated kidnapping.

Douglass said Hall was interviewed Wednesday after police acted on a tip that matched Hall and a vehicle to surveillance video from the Target store parking lot where Smith was abducted Saturday evening.

Smith's body was found about 1:30 p.m. Wednesday about 20 miles east of the abduction site.

Douglass declined to comment on the circumstances of Hall's questioning or evidence in the case, but said police had located a vehicle that matched the description of one seen in surveillance video pulling into the Target parking lot about a minute after Smith parked there.

He said Hall appeared to be the same person shown in the video walking into the Target soon after Smith entered the store.

Johnson County prosecutor Phill Kline said charges would be filed Thursday morning.

"This community has lost a vibrant and promising life and her family has sufferered unimaginable tragedy," he said.

Kline said his office would ask the state to set bond at $5 million.

Officers had been searching woods at the lake since Tuesday after investigators traced two signals from Smith's cell phone to an area about 15 miles east of the Target store in suburban Kansas City.

Before a church memorial service Wednesday evening, Smith's father thanked everyone involved in the search.

"She could walk into a room full of strangers and walk out with a room full of friends," Greg Smith said, fighting tears.

"Her excitement and passion for life was unmatched," he said. "She lived more in 18 years than many people do with a great deal more time."

Police had questioned "numerous people" but had not identified a suspect, Douglass said.

Authorities were still seeking information about a young man videotaped entering and leaving the Target store within moments of Smith. He said police still considered the unidentified man a "person of interest" and not a suspect. (Watch police describe the next steps in the investigation Video)

Asked whether people should be concerned that the suspect could still be at large, Douglass said: "I think we all need to remain vigilant no matter what. I don't want to overemphasize the importance of this, but we always need to use caution."

Smith's parents, Greg and Missy Smith, said Wednesday on "The Early Show" that they do not know the man in the surveillance video. (Watch the teen struggle with her abductor Video)

"None of our immediate family recognize him," Greg Smith told CBS.

Officers also continued to look for information about a dark pickup that was seen entering the Target parking lot shortly after Smith's car. Just before 7 p.m. Saturday, the pickup pulled into the parking lot aisle where Smith had parked about one minute earlier, police said. A man is seen leaving the pickup and going into the Target store Smith had entered.

On Tuesday, police also released video showing a woman they believe is Smith being forced into her car.

Smith, who graduated from high school less than two weeks ago, left the store around 7:10 p.m. and put packages into her car when someone ran toward her, police said. (Watch the teen's parents ask for her return Video)

"You see two individuals come together, and there is no separation of those two individuals," Douglass said. "So it is easy to conclude there was some kind of incident at the back of the car. Then the car leaves."

But the tape was "just not detailed enough" and was being enhanced at a forensics lab, Douglass said.

"We see activity," Douglass said of the videotape. "We are moving on the assumption -- because the prudent thing to do is to treat this as an abduction -- that there was some kind of force involved."

Investigators said they don't know whether Smith was picked at random or abducted by someone she knew.

About two hours after Smith disappeared, her grandparents found her car in a parking lot at a mall in suburban Kansas City with her purse and packages still inside.

The Smith family increased the reward for information about Kelsey's disappearance to $30,000. Greg Smith, who has been in law enforcement for 16 years, described his daughter as an outgoing young woman who planned to be a veterinarian.