The person who now has the cherished items contacted the family demanding money - and police are now involved.
Bernie's daughter, Brooke Fraser, took to Facebook this morning with a post outlining the situation.
She said the unit sold was filled with personal property of "great sentimental value" such as childhood photos, videos, artworks and memorabilia of their dad's rugby years.
"We only became aware of the sale of this unit when an anonymous person, concealing their identity, contacted us with a photograph of some of the personal items they had come into possession of (childhood photos, family letters, etc.). It took our family some time to piece together what had happened and – needless to say - our dad is distraught," she wrote.
But that's when things took an ugly turn as the anonymous buyer refused to sell the property back to the Fraser family, Brooke explained.
"...over the course of days this person continued to significantly raise their price before abruptly announcing they had sold it all to another party," she wrote.
"We are relieved that later they anonymously returned a small box of our family photographs and video cassettes to the storage facility – items that would have been lost forever had they not done so. While we remain extremely grateful to have these photographs and videos back, we are grieved at the loss of the entirety of the rest of the unit and the only memorabilia dad retained of his sporting legacy. The reason we have made the decision to release this statement is in the hope that there is even the slightest chance of recovering ANY of these precious family items."
She asked the public to be on the lookout for any 1970s/early 1980s Wellington rugby or All Blacks paraphernalia on the market such as trophies, awards, certificates, plates and plaques.
Bernie Fraser played 23 times for New Zealand between 1979 and 1984, and made 124 appearances for Wellington.