PORTLAND, Ore. — A graduate student studying conflict resolution at Portland State University was improperly expelled after allegedly threatening violence against faculty, the Oregon Court of Appeals ruled Wednesday.

In its 13-page opinion, the Appeals Court said Portland State officials failed to follow the correct procedures for contested cases when Henry Liu appeared before the Student Conduct Committee.

“Among other things, (Liu) was not allowed to be represented by counsel, cross-examine witnesses or issue subpoenas, and the testimony of witnesses was not taken by oath or affirmation,” Judge Rex Armstrong wrote.

Liu, 37, was banned from campus four years ago after a classmate reported that the student was upset with faculty and said of one professor: “He could get shot.”

Police found four unloaded guns in Liu’s off-campus apartment, along with ammunition and survival gear.

Liu maintained he did not threaten a faculty member, and was expelled based on hearsay. Besides banning Liu from campus, the university released a flier with his photo that told students to call 911 if they saw him on campus.

Liu appeared by telephone at the June 2012 student-conduct hearing because he wasn’t allowed on campus. His lawyer, Michael Rose, could give advice, but wasn’t allowed to make statements or question witnesses.

“The opinion doesn’t have much doubt about what the right answer is,” Rose said Wednesday. “Had PSU been persuadable of the right answer to begin with, a whole lot of time and energy would have been saved, and a lot of emotional trauma to Henry would have been avoided.”

What happens next is up in the air. Portland State could take Liu back, hold another expulsion hearing or petition the Oregon Supreme Court for review.

Portland State spokesman Christopher Broderick said the university disagrees with the court’s reasoning, and is considering an appeal. He said Liu’s ban remains in place for now.

“Student safety was our No. 1 concern, then and now,” he said.

Liu could not be immediately located for comment. Rose said he doesn’t think his client wants to return to Portland State: “But I don’t want to take anything off the table.”