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.