More than 36 hours ago, we were inside the Columbia campus.

We’d heard that protesters in the encampment on the lawn had been told to clear by 14:00 local time (18:00 GMT) on Tuesday.

Media started lining up outside as police erected barriers, with some officers carrying zip wires. There was a sense that something was coming.

When we got inside the encampment itself, it was peaceful - protesters were bathing in the sun, doing school work on their laptops and making sure everyone was fed.

Some were worried police would come in again - but others suggested they wouldn't, given the controversy that ensued after riot police arrested students on 18 April.

Dozens of faculty linked arms to guard the entrance of the encampment. There was a real sense of "the police better not try this again".

Before we left the campus on Monday night, we heard negotiations between students and the university administration had broken down.

But Mahmoud Khalil, lead negotiator and a Columbia student, told us he was optimistic they could get back on track.

On Tuesday we woke up to news that a building inside Columbia had been broken into and occupied, and negotiations fell apart even faster.

Khalil later told us he had been suspended from Columbia. A Palestinian from Syria, he is reliant on a visa to be here. He said he had been promised protections given his position as a negotiator - but he is now unsure about what might lies ahead.

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