(see related) New Delhi, August 21 - One final legal opinion on witness interviews is the sole roadblock to wrapping up a murder investigation involving two Italian marines, an Indian government spokesman said Wednesday. The four witnesses - fellow marines who are thought to have seen what happened the night two of their comrades allegedly killed two Indian fishermen - are at the heart of a dispute over whether they should be in India for interviews by investigators. Italy maintains their presence is not necessary to the investigation of Salvatore Girone and Massimiliano Latorre, accused of murder in the shooting deaths of two fishermen in February 2012. The pair allegedly mistook the fishermen for pirates. The four witnesses could be interviewed long-distance, Italian authorities say. A legal ruling on the issue from the Indian government is on its way, said Indian Foreign Ministry Spokesman Syed Akbaruddin. Italian Defence Minister Mario Mauro said earlier in the day that the witnesses could be interviewed by video conference or by Indian investigators on Italian soil.