What it looks like at every stage when migrant families get separated at the US border

Many migrants are asylum-seekers fleeing violence, oftentimes from Honduras, El Salvador and Guatemala, where MS-13 and other gang violence is widespread.

And because of Trump's new policy, if they're apprehended crossing illegally and don't go through the ports of entry, the parents will be referred for prosecution (it is a federal misdemeanor to cross illegally).

And this is what causes parents to be separated from their children: parents cannot be with their children while in jail awaiting prosecution.

Although if migrant families try to cross at a port of entry, whether they're seeking asylum or not, they will not be charged with crossing illegally, nor will they be separated.

Although there are circumstances in which families can be separated even at a port of entry. For example, if customs has reason to believe the parents and children are not actually family.

But some cross illegally because they don't know that they could be charged and separated, Josh Breisblatt, an American Immigration Council lawyer, told Business Insider.

Or they choose to go between the ports of entry because the lines have become so backed up.

"What is happening is more people are going to the ports of entry, and there are now huge back ups at the ports," Breisblatt said.

"Those people are at the ports of entry in 100 degree heat," Breisblatt said. "I'm sure many of them after a period of time, are exposed to the elements ... and are also at the hands of the cartels."

After migrant families are apprehended illegally crossing the border, they will be taken to a border patrol holding cell.

After 72 hours, the children will be placed into Health and Human Services and either handed over to a family member, guardian or sponsor in the US.

"And that child, many times, is going through their own immigration case," Breisblatt said.

"They are also in their removal proceeding, and they are trying to make their own claim," Breisblatt said. "They do not get counsel, so you have children, sometimes 3 year olds, trying to make claims for asylum in front of a seasoned ICE attorney."

The parents, meanwhile, will be handed over to US Marshals, as they await prosecution, held in pre-disposition holding cells.

After parents seeking asylum are found guilty of crossing the border illegally, they are then placed in an ICE detention center as they wait to get asylum, which can sometimes take a few years.

And this whole time, from when they're separated at the border patrol holding cells until they get asylum, the parents do not see their children.

"There are supposed to be mechanisms for people in ICE detention to at least talk to their kids when they're in HHS custody," Breisblatt said, "but our understanding was those lines of communication are not working well."

And those parents who don't get asylum are then deported -- often without their kids.

If "the parent were to lose their case [for asylum], the kid is still in the United States, and the parent ends up getting deported," Breisblatt said.

"We've been trying to get answers [as to how the parent gets their kid back] ... it seems unclear at this point."

The United Nations and other human rights organizations have argued that Trump's policy violates international law by prosecuting asylum seekers.

The ACLU is also currently suing the US Justice Department over separating families, which spawned from the separation of an asylum-seeking Congolese mother from her daughter.

"The lawsuit cites violations of the Constitution’s due process clause, federal law protecting asylum seekers, and of the government’s own directive to keep families intact," according to the ACLU.

Read more about the case here.