Updated

Police in the small Georgia town of Aragon are stepping up the search for Amber Graham, a 14-year-old ninth grader who vanished eight days ago.

U.S. Marshals and the Georgia Bureau of Investigation will be joining what has been a low-key search for the last seven days as concern for the girl’s safety mounts, Aragon Police Captain Dwayne Alexander said.

According to the girl's godmother, Ruthann Battles Dabbs, Amber's mother last saw her in her bedroom at 11:20 p.m. on Saturday Feb. 20. The girl said she would be ready for church in the morning. Amber's mother looked into the room again at 2 a.m. and discovered that the girl was gone and her bedroom window was open. The mother immediately called the police.

SLIDESHOW: Where's Amber?

Dabbs described Amber as quiet and sensible and said, "She certainly wasn't wild or troubled," adding that the girl's disappearance "was not what she was like." The girl is a petite 5-foot-0 and 90-pounds, with brown eyes and blond hair.

Alexander said Amber, a high school freshman, had "some history of running away," and because of that the search didn’t go into high gear until later in the week. But now, he said, "we are looking at some subjects right now for withholding information and we have conducted several searches.”

He said the last phone call Amber made was to her 16-year-old boyfriend on Sunday morning, “four hours after she was reported missing. They talked for 10 minutes.”

He said a consensual search of the boy's house turned up marijuana in the attic, and since then the boy and his mother have stopped cooperating. "We believe he knows more than he is telling us," Alexander said.

He said police were able to track Amber's cell phone, but "the phone cut off Tuesday and there have been no sightings, no contact since then.”

Ruthann Dabbs disputes the claim that Amber was a runaway or "any sort of problem child, as that claim makes her seem." She Amber left home once, but she left a letter telling her parents where she would be. She said the girl's parents are desperate to hear from their daughter or from anyone who has seen her.

Alexander said efforts to issue an "Amber alert" for the girl were turned down because they couldn’t show that she was specifically endangered.

He said that the particulars of her case were put on the National Center for the Missing and Exploited Children Web site last Friday. Ernie Allen, president of the center, said it appeared the information has not yet been posted and they waiting for a consent form from the mother. "We expect it to be up shortly," he said.

Dabbs said Amber's family has been putting up posters of the missing girl around town all week, but they are being torn down. She also said that police had searched the house of her 15-year-old former boyfriend, and "since then both the boy and his mother had hired lawyers." She said Amber's friends have tried to get them to talk, but they have failed.

She said "The whole town has gone hush-hush," adding that there are rumors flying about that have everyone on edge. "My husband says my involvement is going to get my house blown up," she said.

Dabbs criticized police for failing to act more quickly and said the longer Amber is missing, the more likely it becomes that she has been harmed.

"If they had just searched the area where her phone was last monitored, we would be better off today," she said.