The death of Livye Lewis: A party, a murder, and a man on the run

After a party in Hemphill, Texas, Livye Lewis is discovered dead and her ex-boyfriend Matthew Edgar is found bloodied on the ground nearby. What happened along the side of the road where they were discovered?

source https://www.cbsnews.com/news/livye-lewis-death-matthew-edgar-texas-murder-48-hours/