https://www.reuters.com/article/us-tesla-probe-battery/u-s-regulator-to-send-observer-for-tesla-probe-of-model-s-fire-idUSKBN1JE2M5 >The U.S. National Transportation Safety Board (NTSB) will send a technical specialist to observe a Tesla Inc examination into the causes of a battery fire last Friday involving one of the electric automaker's Model S vehicles in California, the agency said on Monday.