© GettyVehicles line up to enter the US at the border crossing between Blaine, Washington, and White Rock, British Columbia, but along the beach where Cedella Roman was arrested the border is unmarked.
The French citizen was visiting her mother and studying English, when the family headed to White Rock, about an hour's drive from Vancouver in May.
As dusk approached, the 19-year-old went for a jog along the beach. She swerved on to a dirt path as the tide came in, stopping briefly to snap a photo of the stunning scenery before turning around to retrace her steps.
It was then that she was confronted by two officers from the US border patrol.
"An officer stopped me and started telling me I had crossed the border illegally," Roman told Radio-Canada. "I told him I hadn't done it on purpose, and that I didn't understand what was happening."
She hadn't seen any signs marking the border, she said. "I said to myself, well I may have crossed the border but they'll probably only give me a fine, or they'll tell me to go back to Canada or they'll give me a warning."
Complicating matters was the fact that she didn't have any government-issued ID or travel permits on her at the time.
Noting that her steps had been captured on security cameras monitoring the area, the officers detained the teenager and accused her of crossing illegally into Blaine, Washington.
She was transferred to the Tacoma Northwest Detention Centre, run by the Department of Homeland Security, more than 200km (125 miles) south of where she had been apprehended.
"They put me in the caged vehicles and brought me into their facility," said Roman. "They asked me to remove all my personal belongings with my jewelry. They searched me everywhere."
The gravity of the situation began to sink in. "I understood it was getting very serious and I started to cry a bit."
Roman was able to contact her mother from the centre. Christiane Ferne rushed to the facility in a panic, bringing with her Roman's passport and study permits.
It wasn't enough; staff at the centre said the documents would have to be validated by immigration authorities in Canada before they could release Roman, according to Ferne.
Two weeks passed before immigration officials in Canada and the US were able to confirm that Roman was eligible to return to Canada. Throughout it all, Ferne visited her daughter regularly at the centre.
"It was just unfair that there was nothing, no sign at the border," said Ferne. "It's like a trap ... anybody can be caught at the border like this."
Documents issued by the US government and shared with Radio-Canada confirmed that Roman was discharged on 6 June. The family said they were not sure if Roman will be allowed back in the US.
Immigration officials on both sides of the nearly 9,000km border refused to comment on Roman's case, pointing to concerns over privacy.
In a statement, US Customs and Border Protection noted that anyone who enters the US outside an official port of entry is considered to have crossed the border illegally. "This applies regardless of whether or not the individual claims to have inadvertently crossed the border," the department added.
Comment: Any encounter with US border patrol, whatever the reason, is likely to spell bad news. See also: