He was a civil engineer, and having off the afternoon of Monday, May 10, 2003, he rode his bicycle to an area called Parque Forstal. When he saw a police patrol (Carabinero) on horseback, he was interested, and took his photograph. He had absolutely no interest in UFOs. His image shows what appears to be a small being crossing the road during the mounted patrol's journey across a bridge. This is the image that has gone around the world thanks to web sites on paranormal phenomena.
Pereira discussed his photograph at length with reporters, and told them he did not see anything out of the ordinary when he took the photograph, but only noticed the entity when he was transferring photos to his computer. He was well respected in his community, and had no cause to hoax a photograph. He asked for no notoriety, nor financial reward, but willingly shared the photo with the world. His photograph receives a "high credibility" rating from me.