Civil rights groups and members of the United States Congress are pressing for the renewing of an investigation into a 1985 office bombing that killed Palestinian-American civil rights leader Alex Odeh and injured seven people.
The American-Arab Anti-Discrimination Committee (ADC), the National Association for the Advancement of Colored People, Jewish Voice for Peace and others have launched a petition campaign asking the Justice Department to further investigate the explosion, which demolished the ADC's office in Santa Ana, California.
The online petition has about 10,000 signatures.
Loretta Sanchez, a Representative for California, sent a letter to the department in June and is seeking other politicians to sign a letter to Attorney General Eric Holder.
The FBI identified suspects after the attack, but none were ever named or indicted.
"Whenever a leader for a civil rights organisation is killed, it is the responsibility of our country as a whole, and a civil rights community as a whole, to stand up and demand that their killers be brought to justice and to insure that the US Department of Justice does everything in its power to close the case,'' NAACP President Ben Jealous said on Monday.
In 2010, the FBI described Odeh's killing as an "active, ongoing priority investigation'' and noted a $1 million reward.
At the time of the attack, the FBI said they believed the bombing was the responsibility of the Jewish Defence League. A lawyer for the group denied the allegations and asked for a retraction.
Odeh, a regional director for the ADC, was killed as he opened the door to his office on October 11, 1985, the day after he said on television that PLO leader Yassir Arafat was a "man of peace" for his role in securing the release of passengers from the Achille Lauro, a hijacked Italian cruise ship in Egypt.
Odeh, who emigrated from Palestine and became a US citizen in 1977, was described by both Jews and Arabs as a nonviolent man who advocated compromise.
John Conyers, a Representative for Michigan, said on Monday that he wanted the relevant House subcommittee to convene a hearing on the bombing.
"We're going to pursue it vigorously and we're not going to let any more time lapse," Conyers said.
"We're going to continue to help all of the organisations that are involved build up more and more support for us getting to where we ought to be in terms of a horrific, violent crime that has, I think, been put on the back burner for far too long."
The Justice Department had no immediate comment.