The operation at Killen, County Tyrone, close to where the 15-year-old was last seen, has now ended and the Arkinson family have been updated.
The schoolgirl disappeared in August 1994 after a night out across the border in Co Donegal.
Arlene was last seen being driven off down a country road late at night by child killer Robert Howard. He was acquitted of her murder in 2005 by a jury not told about his lengthy criminal history which included killing another teenager, Hannah Williams, in south London several years earlier.
Howard remained the prime suspect in the unsolved case until his death in an English prison last year.