Amanda Trebach, an intensive care nurse who has been trying to keep her migrant patients safe from immigration raids, never expected American law enforcement to use the same kind of violence against her, a U.S. citizen.

But video filmed and posted by fellow organizers during one confrontation with U.S. Immigration and Customs Enforcement (ICE) in August shows Trebach forced to the pavement and roughhoused by federal agents, who violently arrest and detain her.

"You don't know who they are. They don't identify themselves. There's no due process,” she told CBC News.

The incident occurred as Trebach and other members of a Los Angeles activist group called Harbor Area Peace Patrols had been circulating images of licence plates on nondescript vehicles to alert migrant communities to their presence.

On Aug. 8, volunteers were photographing ICE agents leaving a staging site for raids on Terminal Island, whose Japanese residents were the first in America to be displaced and forcibly detained in internment camps during the Second World War .

WATCH | 'They’re scared to go out and get groceries,' activist says of migrants: Migrant patients in Los Angeles are scared to seek medical care, says nurse | Duration 0:25 Amanda Trebach, an ICU nurse and activist with Harbor Area Peace Patrols, says migrants from local communities are avoiding hospitals because masked agents have been known to patrol around them and other public institutions, looking for people to arrest, detain and deport.

Shortly after, the officers stopped their vehicle and jumped out; Trebach says they knelt on her head, handcuffed her and threw her into the back of a black van.

She says ICE “kidnapped” her and told her to stop taking photos.

“I just said, ‘Let me go. We're here. It's our right to monitor you,’” said Trebach. “I'm a citizen.”

Trebach was released without charge hours later.

“As is her constitutional right, Amanda was documenting t