When a black man staying in a Doubletree hotel in Portland, Ore., called his mother from the lobby, he was told by a white security guard that he was trespassing and was escorted out of the building by the police.

The Dec. 22 encounter was captured on cellphone video by the man, Jermaine Massey, who posted it that night on Instagram, where it was shared widely. In other videos, Mr. Massey, 34, acknowledges that he has become part of the continuing documentation, through cellphone videos and social media, of black people being confronted by white authority figures or bystanders while going about their everyday lives.

“I’m afraid to just do normal things now,” Mr. Massey said in an interview Friday, calling the encounter racial profiling. “I’m cautious about what I’m doing, and how people are perceiving that, and I shouldn’t have to think twice about where I take a phone call, or what part of the hotel I can visit.”

Paul Peralta, the general manager of the Portland Doubletree, said in a statement on Saturday that, after an internal review, the hotel had fired the security guard and a hotel manager who was also involved in the encounter.