A Turkish national who is a doctoral student at Tufts University has been detained by federal agents without explanation, her lawyer said on Wednesday.

Rumeysa Ozturk, 30, had just left her home in Somerville to meet with friends Tuesday night when she was detained by U.S. Department of Homeland Security agents, lawyer Mahsa Khanbabai said in a petition filed in Boston federal court.

Video obtained by The Associated Press appears to show six people, their faces covered, taking away Ozturk’s phone as she yelled and was handcuffed.

“We’re the police,” members of the group are heard saying in the video.

A man is heard on camera asking, “Why are you hiding your faces?”