October 13 [Updated 16:00 EDT] -- John Denver, whose folk-pop stylings made him one of the 70s most popular recording artists, has died in a plane crash. According to Reuters, officials have confirmed that the 53-year-old singer was piloting his fiberglass, single-engine experimental plane that went down off of the coast of Northern California on Sunday afternoon.

While Denver's former sister-in-law, Terri Martell, first reported Denver's death to the press early Monday morning, but police did not confirm the identity of the crash victim until Monday afternoon.

In a statement released early Monday morning, the Pacific Grove Police Department released details of the crash, but did not announce the identity of the victim. The police say that at 5:27 p.m. Sunday afternoon the plane was flying approximately 100 yards off of the coast when it unexpectedly dove into the ocean some 130 miles north of San Francisco.

The police went on to say that representatives of the National Transportation Safety Board are due in Pacific Grove on Monday to investigate the crash.

The singer scored 12 platinum albums over the course of his career, which was fueled by hits like "Rocky Mountain High," "Take Me Home, Country Roads," and "Thank God I'm A Country Boy."

Denver also directed a good deal of his energies away from music, supporting a number of environmental causes including anti-nuclear power groups. Denver was also a dedicated supporter of space exploration, and was a board member of the National Space Institute. In 1994, Denver was recognized for his non-music efforts when he was given the Albert Schweitzer Music Award for his humanitarian efforts, becoming the first non-classical musician to earn the honor.