Looking for Liza Leaman of Memel Lithuania

Liza LEAMAN lived in Lithuania in the 1860's. She was married to John WEINBERG and had a son called Jacob who was born on 24 July 1867.Jacob came to New Zealand in July 1892 on the barque Victoria Nyanza. He changed his name to Robert and stayed in New Zealand.
We are trying to trace any records about his family in Lithuania.We know he had at least one brother and sister.