Colorado authorities suspect foul play in the case of a missing mother who worked with an escort service and who hasn't been seen in more than a week.

Paige Birgfeld, 34, of Grand Junction, Colo., has not been seen or heard from since June 28. Police found her burning car in a parking lot a couple of miles from her home a day after the mother of three was reported missing.

"Nothing during the course of our investigation has lead us to believe that Paige walked away from her family or that she left of her own free will," said Mesa County Sheriff Stan Hilkey in a statement released Saturday.

"Unfortunately, we do suspect foul play in her disappearance and the subsequent arson of her vehicle."

Mesa County authorities have focused their search on persons of interest with whom Birgfeld may have come into contact while working for an escort service, Models Inc. She was known to her customers as "Carrie," police said.

Birgfeld's red Ford Focus was found ablaze in a business parking lot about 2 miles from her home on July 1.

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Authorities have used bloodhounds to search Birgfeld's home and torched car.

Her family believes she may have run into foul play in her work with the modeling agency and escort service.

"She was here in Grand Junction, and there was nothing out of the ordinary," her father, Frank Birgfeld, told the Denver Post last week. "And then she simply vanished."

Click here to read the Denver Post report.

Paige Birgfeld posted messages in March on www.chefsuccess.com indicating she feared the return of one of her ex-husbands, Rob Dixon, the Grand Junction Daily Sentinel reported last week. She wrote that her children asked if their dad was going to kill her.

Dixon was arrested on charges of domestic violence after allegedly shoving Birgfeld during an argument and later pleaded guilty to the lesser charge of harassment, the Denver Post reported.

Investigators have questioned Dixon and said he is cooperating fully. Dixon's attorney told the Post he was in Philadelphia working as a paramedic the week that Birgfeld disappeared.

On Monday night, about three dozen family members and friends held a candlelight vigil for Birgfeld to pray for her safe return.

Birgfeld is described as 5 feet 4 inches tall, weighing 110 pounds. She has sandy hair and hazel eyes and last was seen wearing a blue strapless top with flowers and blue denim shorts. She also goes by Paige Dixon and Paige Beigler, authorities said.

Anyone with information was asked to call the Mesa County Sheriff's Department at 970-244-3500.

The Associated Press contributed to this report.