Since January 1984, a team composed of border patrol agents and San Diego police officers has disrupted the lucrative business of criminals who rob and brutalize illegal immigrants crossing the border and then escape back into Mexico. Two border patrol officers of the unit, however, have been wounded in shooting incidents. Most aliens come from hamlets in Mexico's interior where the economy has collapsed. They pay guides to help them make the illegal crossing, but the guides often inform bandits on the intended crossing point. The unit not only has to apprehend the bandits, but convince the victims to press charges. Hours of operation are varied to counter the bandits' and guides' effective intelligence grapevine. Border patrol officers feel that the 12-foot-high wire mesh fence known as the Tortilla Curtain along the border between Mexico and El Paso, Tex., has done little to stop the flow of illegal aliens. In addition, smugglers have become more sophisticated as the market for their services grows. The El Paso sector of the border must cope with 400 to 700 illegal crossings a day. Border patrols also encounter inattentiveness from lawmakers in Washington who see immigration as a social problem, hostility from Hispanic groups, and a social and economic environment that encourages aliens to break the law: smugglers want money and employers want cheap labor. One chief of the El Paso sector gained the admiration of his troops by rounding up 21,600 aliens in 2 months through surprise raids on nightclubs, bars, farms, ranches, and early morning river crossers, but he left town with a Federal class action lawsuit over his head. The sector unit now claims that the local illegal alien problem is under control and is concentrating on smugglers and illegal aliens headed to the interior. Photographs are included.