Authorities arrested 28 people outside the White House Tuesday during a protest to support the release from prison of Mumia Abu-Jamal.

The protesters, dressed in mock prison jumpsuits, were arrested for not dispersing from the sidewalk in Lafayette Park by U.S. Park Police about 5:30 p.m. Police arrested 27 on charges of failure to obey a lawful order, a misdemeanor. One other person was arrested for interfering with agency functions, said Sgt Paul Brooks, a Park Police spokesman.

Protesters chose Tuesday to protest because it was Abu-Jamal’s birthday. Their efforts included a rally outside the Department of Justice and a march downtown that culminated at the White House, they said.

Abu-Jamal was once sentenced to death after being found guilty of killing a police officer in Philadelphia about 30 years ago. But in December 2011, prosecutors abandoned their effort to execute Abu-Jamal. For decades, his supporters have maintained that he was victimized by a discriminatory legal system.

Clarence Williams is the night police reporter for The Washington Post and has spent the better part of 13 years standing next to crime scene tape, riding in police cars or waking officials in the middle of night to gather information about breaking news in and around Washington.