American-Born Gangs Helping Drive Immigrant Crisis at U.S. Border

``Thousands of the Salvadorans and Nicaraguans who fled their countries at the time landed in Los Angeles, where they found relatives and a Latino culture that felt like home. But their arrival also fueled new tensions in Los Angeles's youth culture, historians and gang experts say. Some Mexican-American and African-American gangs that were established in Los Angeles targeted newly arrived Central Americans. ''