Investigators continued searching a missing Maple Grove girl's home Friday and plan to keep digging outside with backhoes and other equipment throughout the Memorial Day weekend.

"We're going to work until we're done," Maple Grove Police Capt. Keith Terlinden said Friday. "We are searching the entire property."

Attention on the 25-year-old case of Amy Pagnac, the 13-year-old who disappeared in 1989 after a trip to her family's farm, re-emerged this week when police, Hennepin County and FBI investigators showed up at the home with a sealed search warrant.

Since then, Susan Pagnac and Marshall Midden have stayed with their daughter, Amy's younger sister. They said they don't know why police are searching their home and yard. But they remain hopeful their daughter, who would now be 37, will be found alive.

"I want them to stay focused on their job," said Susan Pagnac, adding that police haven't said how long the couple will be displaced. "I don't expect to hear anything from them until they complete whatever they need to complete ... and neither should I; I want them to stay on task."

Marshall Midden told police he and Amy went to tend crops at their farm in Isanti County about noon Aug. 5, 1989, and were returning home about 5 p.m. when he stopped at a gas station 2 miles away from the family's home. Midden told police he used the bathroom, came outside to find the car empty and assumed Amy was using the women's bathroom. But she had vanished.

When he called his wife to tell her Amy was missing, she said she knew something was wrong. Despite Amy having wandered off before, Pagnac said nothing was unusual with her daughter besides a headache the night before. In fact, the two had planned to shop for school clothes that night.

The couple believe that Amy had a seizure and became disoriented, or was abducted for sex trafficking, because years later, they say, an investigator told them Amy had been seen at a strip club. And in 1992, the couple says, someone was approached at a train or bus station by a girl who said, "I'm Amy Pagnac."

The 13-year-old girl disappeared just over two months before 11-year-old Jacob Wetterling was abducted at gunpoint by a masked man near St. Joseph. But while Wetterling's case captured the state's attention, Pagnac's wasn't covered because, her parents say, police treated it as a runaway.

"It's been hard," Susan Pagnac said.

She said police searched their home in 1990, and in 2007, they searched there and their farm, which they said was used to grow organic vegetables but hasn't been farmed since 1993. "Nobody has thoroughly searched what Amy had," Susan Pagnac said, adding she's hopeful some note or item of Amy's will help investigators locate her. "These are procedures that need to be done."

Now, the home is the scene of an extensive investigation in the quiet residential neighborhood. Mike Haller grew up there and knew the family. He watched Friday as several police cars lined the street while a backhoe dug up dirt, filling a dump truck as investigators carted crates into a storage unit.

"It's kind of crazy; I'm still in shock," he said, adding that the missing case is all the neighborhood is talking about. "If anything, it could bring closure to everything."

Kelly Smith • 612-673-4141

Twitter: @kellystrib