Updated

Colorado authorities are baffled by the case of a missing mother of three and are investigating whether she may have staged her own disappearance.

Paige Birgfeld, 34, of Grand Junction, Colo., has not been seen or heard from since June 28. The Mesa County Sheriff's Department is still listing it as a missing persons case.

"We're looking into all possibilities, whether she walked away or someone took her away," Heather Gierhart, a spokeswoman for the Mesa County Sheriff's Department, told FOXNews.com. "At this point we really don't have anything that would indicate one over the other."

On Sunday night, Paige Birgfeld's red Ford Focus was found ablaze in a business parking lot about two miles from her home. Lt. Jim Fogg of the Mesa County Sheriff's Department said authorities have not ruled out a random act of vandalism.

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"It definitely does raise suspicion, but there isn't anything additional than that at this point that would indicate that we should change our investigation to something other than a missing person," Gierhart told FOXNews.com.

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

Her family, who reported her missing on June 30, believes she may have run into foul play in her work with a 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. "And then she simply vanished."

Click here to read the Denver Post report.

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 reports. 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 Paige Birgfeld disappeared.

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

Paige Birgfeld is described as 5-foot-4-inches tall, weighing 110 pounds. She has sandy hair and hazel eyes and was last 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 is asked to call the Mesa County Sheriff's Department at 970-244-3500.

FOXNews.com's Sara Bonisteel and the Associated Press contributed to this report.