(Portland, OR) -- The Multnomah County Medical Examiner is investigating four deaths as being heat-related. They all happened on Monday. The first death was a 47-year-old man in Northeast Portland who was witnessed dying. The second death was a 64-year-old man in Southeast Portland, then a 70-year-old woman in Gresham, and an 82-year-old woman died in Southwest Portland. It can take several weeks to months before a death is confirmed as being caused by the heat.