By Joanna Plucinska WARSAW(Reuters) -Major leaks that suddenly erupted in the Nord Stream gas pipelines that run from Russia to Europe under the Baltic Sea have generated plenty of theories but few clear answers about who or what caused the damage. Here is what we know and what has been said so far: WHO IS BEING BLAMED? As probes by European authorities continue, the Swedish security police said on Thursday that suspicions of gross sabotage on the pipelines had been strengthened following a crime scene investigation. The Danes are also carrying out an investigation, with both countries excludi…