Salt Lake City ? A gunman broke into a home and took a 14-year-old girl from her bedroom Wednesday, warning the girl’s younger sister he would hurt her if she told anyone what she saw, police said.

Police, some with tracking dogs, began searching the foothills for Elizabeth Smart before dawn and authorities used a statewide emergency alert system for the first time to quickly broadcast information about a missing child.

At a late afternoon news conference, Elizabeth’s father appealed for her safe return.

“Elizabeth, if you’re out there, we’re doing everything we possibly can to help you. We love you, we want you to come home safely to us,” Edward Smart said.

Mayor Rocky Anderson also announced a $10,000 reward offered for information about Elizabeth’s disappearance.

Police said there was no indication the man knew Elizabeth, but authorities were looking at the family’s computer to see if the girl had contacted strangers online and interviewed the eighth-grader’s classmates at Bryant Intermediate School.

Elizabeth’s 9-year-old sister waited several hours before alerting her parents about the abduction because of the threat, police said.

The sister told police that the soft-spoken man got into the house by forcing open a window and had a small black handgun. Elizabeth was wearing red pajamas, and the man let her take a pair of shoes, police said.