Updated

The mother of missing New York teen Brittanee Drexel thinks her daughter could be dead after going on a spring break trip to Myrtle Beach against her wishes.

Dawn Drexel told WHEC News 10 in Rochester, N.Y., that her daughter would never run away.

"I seriously think someone took my daughter or she may not be alive," Dawn Drexel said.

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Brittanee Drexel, a junior at Gates-Chili High School in Rochester, left the Bar Harbor Hotel in Myrtle Beach at about 8 p.m. on April 25 to visit a friend named Peter Broswick, who was with a group of male friends at the nearby Blue Water Resort.

Police released new surveillance camera footage Monday of the teen on her way to the hotel.

Detectives think Broswick may have been the last one to see the missing girl alive.

Broswick, who is also from Rochester, left Myrtle Beach to return home about 1 a.m. the night Brittanee was last seen, according to News Channel 15's CarolinaLive.com. He and several others were questioned, but were cleared as suspects, according to Brittanee's mother.

"As far as I know, they’ve done what they needed to do as far as those boys are concerned back home," said Dawn Drexel. "They’re not persons of interest anymore."

South Carolina authorities focused their search over the weekend on an area just south of where the teen disappeared after pinpointing the last place her cell phone gave off a signal.

Searchers using dogs, helicopters and boats concentrated on a 7-mile area along the South Santee River and U.S. 17.

Brittanee's cell phone signal was captured April 26, a day after police say the teen was last seen.

Myrtle Beach Capt. David Knipes told reporters the search hasn't yielded any new clues in the case.

Dawn Drexel has said she's concerned because the teen suffers from depression. The girl may have been upset because she and her husband are getting divorced, Drexel said.

Brittanee's mother added that she didn't want her daughter to go to Myrtle Beach, but the girl had "her mind set" on the trip and went anyway. They continued to keep touch by phone — until the contact ended abruptly the night the teen disappeared.

Family and friends spent the past week canvassing popular beach clubs and hangouts in the resort town without any results.

Brittanee Drexel has blue eyes and shoulder-length brown hair with blond highlights. She's 5 feet tall, weighs about 100 pounds and was last seen wearing a multi-colored shirt, black shorts and flip-flops.

Those with any information are asked to call Myrtle Beach Police at (843) 918-1300, 1-800-CRIME-TV or 1-800-THE-LOST (843-5678).

Click here to visit HelpFindBrittanee.com.

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The Associated Press contributed to this report.