By Arezow Doost, CBS 11 News

PLANO (CBSDFW.COM) – A missing fitness instructor may be the victim of foul play.

Plano Police are searching for Susan Loper, 40, from Frisco and say she hasn’t been seen since early Tuesday morning. Those closest to her pray she’s safe.

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“We want her back,” says best friend Julie Mitchell. “She is extremely happy and positive.”

Investigators believe the single mother was abducted from Gleneagles Country Club in Plano. She’s been a pilates instructor there for more than 16 years.

Tuesday morning she missed several appointments.

“She is a very routine driven person. She has never not done what she was going to do. She has never stood up an appointment,” explains Mitchell.

Mitchell says her friend wouldn’t have left her 8-year-old son Jake, who is autistic.

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“He is special needs and she has gotten him to a point where he is symptoms free of everything,” says Mitchell.

Investigators say they have not been able to find her white 2010 Toyota Rav4. It has a Texas license plate number of BR4 C986.

They do believe she arrived at the country club, since all of her belongings were there.

“Everything there that our investigator located … things they found there makes us believe this was a possible abduction,” says Rick McDonald with the Plano Police Department.

Loper was supposed to open her own studio this Friday.

She was last seen wearing yoga clothes, which were black tights and a workout top along with a red jacket and flip flops.

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Update – 8:37 A.M. According to reports, police recovered her car in the area of Preston Road and the Dallas North Tollway. Investigators have located evidence in the vehicle to substantiate this case as an aggravated kidnapping.