One full week after pro-Palestinian protesters at Columbia University reported a suspected chemical attack during an on-campus protest, no arrests have been made in the incident.

Police have said they’re investigating at least six reports related to the incident, which activists believe was a deployment of “skunk,” a foul-smelling crowd control chemical spray often used by Israeli police and military forces in Palestinian neighborhoods. The smell of the chemical has been compared to raw sewage and decaying meat, and it’s known to permeate clothing and other surfaces.

The suspected chemical attack last Friday led to numerous hospitalizations and reports of nausea, vomiting and dizziness, according to organizers.

The incident has sent shockwaves through Columbia’s campus over the past week.

After a protest advocating for divestment from Israel that included the groups Jewish Voice for Peace and Students for Justice in Palestine — both of which were suspended by Columbia last year — numerous participants realized that they’d all experienced a similarly foul smell and corresponding physical symptoms at the protest.

Palestinian protesters at the university said after the demonstration that they recognized the smell from its use in the West Bank.

Up to 10 protest participants were hospitalized in subsequent days, Maryam Alwan, a leader in Columbia’s Students for Justice in Palestine chapter, told HuffPost. Alwan described students’ frustration at what they felt was a hostile atmosphere toward criticism of Israel on campus.

“We do not feel protected by the school. We do not trust the school,” she said. “They haven’t really done anything about hundreds of reports of unrelenting harassment for months now.”

Organizers grew frustrated with the university’s response and faulted them for initially downplaying the attack. As The Intercept reported, school administrators appeared to fault protesters for holding a demonstration that was “unsanctioned and violated university policies and procedures which are in place to ensure there is adequate personnel on the ground to keep our community safe.”

But after organizers began collecting and sharing stories of students affected by the suspected chemical attack, the administration’s response grew more pointed.

On Monday, Interim Provost Dennis Mitchell announced that “the alleged perpetrators identified to the University were immediately banned from campus while the law enforcement investigation proceeds,” but he did not identify the perpetrators, nor did he confirm the nature of the incident aside from saying that students who’d attended the protest “later reported being sprayed with a foul-smelling substance that required students to seek medical treatment.”

Mitchell said the New York Police Department was investigating what he described as “what appear to have been serious crimes, possibly hate crimes.”

The Columbia Spectator reported a couple of days after the demonstration that nearly two dozen students had attested to experiencing the foul smell, physical symptoms, or property damage. It reported Wednesday that Columbia administrators had requested access to photos and videos from the student paper. The Spectator posted the material online instead.

Spokespeople for the university declined HuffPost’s request for more details about the investigation.

The police were similarly tight-lipped. ABC News, citing unnamed police sources, reported Tuesday that the investigation did “not fall within the parameters of a hate crime investigation,” but NYPD spokespeople did not confirm as much to HuffPost when asked directly.

“There are no arrests, and the investigation is ongoing,” a spokesperson said.

The NYPD public information office previously said one victim made a report Friday after they “began to feel nauseated and experienced a burning sensation in her eyes” and that five more reports were filed Sunday.

For days after the attack, Alwan told HuffPost, the administration failed to reach out to affected students directly, leaving them feeling abandoned and under threat.

She said, “This attack only could have happened in a hostile environment.”