NBC News reports that the Department of Homeland Security has had paid informants inside the migrant caravan to keep an eye on their activity. DHS has also been monitoring the communications used to organize the caravan:

The Department of Homeland Security is gathering intelligence from paid undercover informants inside the migrant caravan that is now reaching the California-Mexico border as well as monitoring the text messages of migrants, according to two DHS officials.

The 4,000 migrants, mainly from Honduras, have used WhatsApp text message groups as a way to organize and communicate along their journey to the California border, and DHS personnel have joined those groups to gather that information…

On Monday, DHS officials told reporters that their intelligence on Sunday night had indicated that a group of migrants wanted to run through the car lanes of a border crossing near San Diego. Customs and Border Protection shut down all northbound lanes of the crossing from 3 a.m. to 6 a.m. as a result. However, the ambush was never attempted.

Yesterday DHS Secretary Kirstjen Nielsen revealed on Twitter that lanes at the San Ysidro Port of Entry were closed after DHS learned some migrants were planning to rush the border. I guess we now know how DHS got that information:

Rushing the border is exactly what the caravan did at the southern border with Mexico last month. A large crowd pushed through the Guatemalan side of the border crossing and then got stuck on the Mexican side of the river.

When the caravan got stuck on the Mexican side by a tall gate and a large number of Mexican federal police, many wound up crossing illegally via rafts across the river.

Finally, DHS held a conference call with reporters and claimed that up to 500 members of the caravan have criminal records. From Fox News:

More than 500 criminals are traveling with the migrant caravan that’s massed on the other side of a San Diego border crossing, homeland security officials said Monday afternoon.

The revelation was made during a conference call with reporters, with officials asserting that “most of the caravan members are not women and children”. They claimed the group is mostly made up of single adult or teen males and that the women and children have been pushed to the front of the line in a bid to garner sympathetic media coverage.

The remainder of the caravan (actually three separate caravans) are expected to arrive in Tijuana this week. The total number of migrants waiting to make asylum claims will then reach approximately 10,000 people. But U.S. authorities are only processing 100 claims per day, so processing everyone will take up to six months. Meanwhile, some Tijuana residents are not happy at being asked to feed and shelter a large number of migrants in their city. One local protester told the LA Times, “We demand respect! We demand that our laws be followed.”