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FRISCO (CBSDFW.COM) – Authorities in Frisco continue their search for a North Texas mother and her three children, all missing after last being seen near their home on Monday. Police have been tracing credit card purchases, toll tag use and even domestic violence shelters in hopes of finding the missing family.

Neighbors were shocked and saddened by the sudden disappearance of 39-year-old Christine Woo along with her 5-year-old daughter, 3-year-old son and 1-year-old daughter. They have been living in their Frisco home for less than a year. Also missing is the family’s silver Honda Pilot with the Texas license plate BT3-D622.

According to police, when husband and father Brandon Woo returned home from work on Monday night, his family was gone. There was no sign of marital trouble. In fact, the couple had recently started volunteering at Stonebriar Community Church. A church spokesman explained that the missing woman’s cell phone was found at home, and her most recent calls were to other church members.

The trail of the missing family seems to end Monday afternoon. Woo used her credit card at two locations — a Walgreens store and a McDonald’s near their home. The card has not been used since those transactions.

Police have not issued an Amber Alert in this case because, other than the mysterious circumstances surrounding the family’s disappearance, there is no actual evidence that Woo and her kids are in any danger. There is nothing that points to this being a kidnapping incident.

“In a situation like this, it’s concerning to us all,” said Jeff Inmon with the Frisco Police Department, “if somebody disappears and nobody’s heard from them for a few days. Like I said, we have no information that they’re in any kind of danger, however, at this time, we are just trying to make sure they are okay.”

Woo has been described by authorities as a woman of Asian descent, 5 feet 3 inches tall and about 120 pounds. She has brown eyes and black hair. Friends and neighbors added that the Woo family was happy, friendly and outgoing. Nobody has any clue as to how or why the mother and her children disappeared.

Anyone with information about the location of Woo or her kids is urged to contact the Frisco Police Department immediately at 972-292-6010.