My 10 year-old son and I were camping at a remote ranch in northern Tamaulipas, Mexico. The purpose of our visit to the ranch was archaeological explorations of Indian campsites, which I have been exploring regularly since 1982. The ranch is located on the Rio Grande, about 5 miles northwest of the city of Zapata, Texas. Our campsite is located on a small plateau about 1/2 mile west of the river. I have been a police officer since 1993. My background (field of study) is astronomy and archaeology. We arrived at the ranch, the Rancho San Fabian (ca. 4,500 acres) late in the afternoon of April 16, 1999. We managed to get in about 1 1/2 hrs. of exploration before we had to proceed to our campsite to get set up for the night ahead. We planned to spend the entire next day exploring the myriad archaeological sites on the ranch. This ranch is very remote, and the nearest Mexican city is Nuevo Laredo, some 40-45 miles north. In 1999 there still was no electricity on the ranch. My archaeological field notes for the date in question (04/16/99) indicate that my son and I started gathering firewood in the area of the camp, but I left briefly to gather more a short distance from the camp. Upon my arrival my son reported a close encounter with a coyote while I was gone. We started a campfire, the only light in this very dark area. The fire was started at about 8:35 p.m. My notes indicate that it was a very pleasant evening, and an owl was heard hooting in the area. A few minutes after getting a roaring fire going, I noticed a bright clustering of white lights low in the southwestern skies, a few degrees above the horizon. There is a north to south trending ridge that runs about 1/2 mile west of our campsite, otherwise the view of the sky is uninhibited. The only trees in the immediate vicinity are low, thorny mesquite trees. The cluster of lights were obviously moving, but I was unsure how far away they were. The lights appeared to be getting slowly closer, and they traveled on a course that led them to a point due west of our campsite. At one point I realized the lights were getting much brighter, and I suddenly realized they were moving directly towards our position on the barren plateau. My first thought was that the lights were from a Mexican military helicopter, and they (Mexican military officials) had spotted out campfire. However, I strained to hear the sound of helicopter rotors, but no sound was heard. I still believed it was a helicopter, and the object was getting much closer. I expressed concern to my son that the percieved military helicopter might attempt to land at our campsite. He became obviously distressed, and I ordered him to flee with me into the brush just east of our campsite. The area we fled to was in a gully that runs on the east edge of the plateau where our camp is located. My intent was to take cover in the darkness away from the brilliantly illuminated (by the roaring campfire) campsite. However, it did not take long to realize that there was no sound, and the lights, a "V"-shaped assemblage of five quite bright white (w/slight yellowish tint) lights appeared to be affixed to a triangular-shaped aircraft that was flying directly towards us. The point of the "V" was oriented in the direction the object was flying. The object traveled at an unknown height from west to east, to a point approximately 75 degrees above the west horizon (nearly overhead, but not quite). My son and I hunkered down in the brush, quite amazed at what we were seeing (and not hearing!). The object banked slowly left (north) and angled in a direction generally toward the distant city of Nuevo Laredo. At its closest approach the object stretched approximately 10-12 degrees in maximum width. The object then began banking slowly toward the northwest horizon and it soon disappeared from sight. It is noteworthy that the object was more difficult to see (dimmer)after its closest approach to our camp. The lights appeared to be blocked somewhat by the object itself after it began to fly away from our location. My son and I soon returned back to our campsite, where our vehicle was parked a few yards from the campfire. We discussed what we had seen for a while, quite mystified. However, necessary chores still needed to be performed, so we attended those duties, including preparing supper and generally organizing our camp.We kept a close eye on the sky, and I made a note that the skies were clear and very dark and transparent, and stars were clearly visible all the way down to the horizon. The M13 globular star cluster in Hercules was easily visible to the unaided eye, and the M51 "Whirpool" galaxy in Ursa Major was easily visible in 10x50 binoculars. I also noted that the Omega Centauri (globular) star cluster, low above the southern horizon, was very bright to the unaided eye and partially resolved into stars with the 10x50s. I also noted that during the evening hours my son and I observed (AND HEARD) numerous high-flying large jets traversing the sky in a north to south direction several miles west of our campsite. This is along a well traveled route used by airliners and large freight jets. These fly at about 30,000 feet during their long journeys to southern destinations. Additional notes indicate that it was a quite cool night away from the campfire, necessitating the use of light jackets. I noted that my son, Jeremy, finally went to sleep in the truck at about 11:10 p.m. and I followed at about midnight.My son was so impressed by the object we had seen that the following day while still at the ranch he made a sketch of it. However, his sketch shows a triangular-shaped object with 7-9 lights on its leading edge, whereas the actual object we saw had five lights, with one at the apex of the forward "point," and two lights on the leading edge of each rearward trending "edge." We have spoken about the sighting of the strange object many times in the intervening years, but the memory of the event is still quite vivid in my mind. It is enhanced by the fact that notes about the incident were incorporated into my archaeological field journal at the time (Expedition #687). I have been interested in astronomy since 1974, and have watched the sky regularly since then. I am quite familiar with the various objects in the sky, both natural and man-made. I am also familiar with most types of conventional aircraft, and this was most certainly not one of those. I am certain that it was a single craft, but don't know its origin, obviously. I would be inclined to believe that it may have been a high-tech experimental aircraft, but what troubles me is why such a craft would be operating over this remote and not very extraordinary part of Tamaulipas, Mexico. There is nothing of a strategic nature anywhere in the region, save the U.S./Mexico border itself.