The number of people taken into custody after illegally crossing from Mexico into the United States dropped in June for the first time in six months, plummeting by more than 37,500 since May, according to two officials with firsthand knowledge of the data.

Exactly 94,487 people were arrested crossing between ports of entry in Texas, New Mexico, Arizona, and California last month. The massive decline comes after 132,000 illegal entrants were arrested in May on the southern border, the highest number in one month since March 2006.