A couple held a runaway teen captive in a hollow bed frame for weeks and forced her to have sex for money with people they found on the Internet, police said.

The 15-year-old girl managed to call family members for help while 18-year-old Matthew Gray and 19-year-old Janelle Butler were sleeping Monday night, authorities said. The two were arrested Tuesday.

The girl ran away from her El Mirage home in September and met the couple through a friend about three hours after she disappeared, police Sgt. Andy Hill said. They took her to a park, bound her and had her gang raped for hours, police said.

At a west Phoenix apartment, they imprisoned her in a dog kennel for about a week and threatened her with a gun, Hill said. They sold her for sex dozens of times on the Internet, he said, and forced her to hide in a hollowed-out bed frame covered with plywood.

"She was tortured. She had a gun pointed to her head. She was told that if she tried to escape or said anything she would be killed, her family would be killed," he said.

On Monday evening while Gray and Butler were sleeping, the girl called her family and told them she was being held. She knew the general area but couldn't say exactly what address or apartment she was in, Hill said.

Investigators said they had received tips about a runaway in the complex during the past several weeks, but could not find the girl. A neighbor, Lorraine Montoya, said the couple approached her and asked if she would hide the runaway weeks ago. She refused.

"When they told me she was a runaway, I called the cops right away," said Montoya.

Police repeatedly questioned Gray and Butler, until Butler broke down and told investigators she was in the bed frame, police said. The girl underwent a medical exam and was later released to her parents.

Gray was booked on hundreds of counts, including sexual assault, kidnapping and child prostitution. Butler was booked on kidnapping, child prostitution and other charges. Both were being held without bond.