The college reportedly attended by Mohammed Emwazi, the British ISIS executioner who appeared in a number of beheading videos made by the Islamic State group, said Thursday it was “shocked and sickened” by the fact that Emwazi roamed its halls before joining the militant group. Emwazi, of West London, was widely reported as the identity of “Jihadi John,” who gave warnings to the U.S. not to intervene in Iraq and Syria, where ISIS occupies large swaths of land, before Americans hostages were shown beheaded in the videos.

“A Mohammed Emwazi left the University six years ago. If these allegations are true, we are shocked and sickened by the news. Our thoughts are with the victims and their families,” a representative for the University of Westminster in London told the Telegraph. “We have students from 150 countries and their safety is of paramount concern. With other universities in London, we are working to implement the government’s prevent strategy to tackle extremism.”

Emwazi, 26, reportedly holds a degree in computer programming from the university and was believed to have traveled to Syria in 2012, according to the Washington Post. Emwazi was given the nickname Jihadi John by some of his captives, Asim Qureshi, an official with a British human rights group CAGE, told the paper. Qureshi said his group was in contact with Emwazi before the alleged jihadist left for Syria.

“There was an extremely strong resemblance” between Emwazi and the “Jihadi John” shown in the beheading videos, Qureshi said. “This is making me feel fairly certain that this is the same person.”

According to Emwazi’s case file on CAGE’s website, he was born in Kuwait in 1988 and moved to the U.K. when he was 6 years old. The group said Emwazi “was subjected to security agency harassment for at least four years,” including threats from the British domestic intelligence service, MI5, which attempted to recruit him as an informant.

After graduating from the University of Westminster in 2009, Emwazi planned a summer vacation to Tanzania but was stopped at the airport and put in jail before being put on a flight to Amsterdam, according to CAGE. There, Emwazi was interrogated by men purporting to be from the Dutch intelligence service and MI5. The agents said they believed Emwazi actually planned to go to Somalia, not Tanzania. Without explanation by CAGE, the interview turned from accusations to courting Emwazi to work for MI5.

Emwazi’s bags were searched and he was stopped by men claiming to be from the U.K.’s Anti-Terror Unit, according to CAGE. He was questioned about the 9/11 attack and the 7/7 attack in London, and they also brought up that they spoke to Emwazi’s fiancée. The interaction with authorities scared off the fiancée, CAGE claimed, and Emwazi planned to settle in Kuwait to avoid harassment. Emwazi was in the Middle Eastern nation for eight months and worked for a computer programming company when he was harassed again while going to London in late May 2010 to visit his family.

He was stopped at Heathrow Airport and had his passport, cell phone and SIM cards taken from him as part of a “routine check about passports,” according to CAGE.

Later in 2012, Emwazi “chose to completely change direction in pursuing a future life outside of the U.K.” and sought to work for an English language center in Saudi Arabia, but he was rejected. In early 2013 he changed his name to Mohammed al-Ayan, but U.K. authorities prevented him from going back to Kuwait a third time.

He left his parents’ U.K. home in 2013 and was reported missing after they didn’t hear from him for three days, according to CAGE. Police told the family that they had information that Emwazi entered Syria, although his family was skeptical, the group said. They said their son eventually told them he was helping Syrian refugees in Turkey.