I wonder if the neighbor's recollection of the date he/she saw Ritchie is incorrect. According to the article, park rangers said his vehicle had been there for approximately two weeks before he was reported missing April 30. That would put his vehicle there mid-April. Of course, that doesn't mean he was also there around that time. Also noted that LE did a welfare check at his home a week after the vehicle was first noticed, and were unable to make contact with anyone.
Info from the article slowpoke posted above.
Info from the article slowpoke posted above.