Full Story: http://www.tmz.com/2016/01/18/glenn-frey-the-eagles-dead/ Glenn Frey, co-founder and guitarist for the Eagles, has died ... TMZ has learned. We're told the cause of death was a combination of complications from rheumatoid arthritis, acute ulcerative colitis, and pneumonia. Frey had been battling intestinal issues for months and had surgery in November. We're told in the last few days his condition took a turn for the worse. He died in New York City.