Border Patrol San Diego arrests plummet in 2012 San Diego Chief Patrol Agent Paul Beeson said at a community meeting in Alpine Wednesday that agents made about 28,400 apprehensions in the sector during the fiscal year that ended Sept. 30. Last year's tally is lowest since 1968 in the San Diego sector — the busiest corridor for illegal immigration into the U.S. from Mexico until the late 1990s.