On March 10, 1977, the city was in the midst of the second day of a bloody three-day hostage standoff with terrorists, where 12 gunmen occupied three buildings, including the District’s seat of government, killed a radio journalist and police officer, and wounded then-D.C. Councilmember Marion Barry.

The hostage-takers, led by the founder of the Hanafi Movement in the United States, Hamaas Abdul Khaalis, threatened to kill more people—in all, 149 hostages were held at the District Building, the D.C. offices of B’nai B’rith, and the Islamic Center of Washington on Embassy Row—unless a movie they deemed sacrilegious to Islam was destroyed.

Opponents of Khaalis, including two members of the Nation of Islam, had killed members of his family four years earlier. They had been convicted and sentenced to life in prison, but that wasn’t enough for Khaalis, who was seeking vengeance. As Time magazine wrote at the time:

That five of the killers of his family were eventually convicted and given life sentences did not satisfy Khaalis. His religion, he felt, demanded justice in a jihad—a holy war. For years he brooded; then last week he struck….

Armed with rifles, shotguns, and machetes, the Hanafi terrorists, under Khaalis’ personal command, first struck the B’nai B’rith offices on Rhode Island Avenue NW around 11 a.m. on March 9. They seized dozens of hostages, “shooting at some, slapping and cutting others.” Just after 12 noon, three gunmen entered the Islamic Center on Massachusetts Avenue NW, taking 11 hostages but not firing any shots.

The third assault, on the Wilson Building (then known as the District Building) was much more violent. As Time wrote:

The last and bloodiest attack took place at 2:20 p.m., when a pair of trigger-happy gunmen invaded the District Building, two blocks from the White House and only 300 yards from the Washington Monument. They began shooting indiscriminately. A black radio newsman, Maurice Williams, 24, was hit and killed instantly. A city councilman, Marion Barry, was shot in the chest. Two other people were wounded.

“It’s been a long time, but some things you never forget,” Barry, who would go on to be mayor and is now a councilmember again, told The Washington Post on the 30th anniversary of the standoff. “That’s one of them.”

Barry helped unveil one of two memorial plaques in the Wilson Building’s press room, which is now dedicated to the memory of Williams, the WHUR radio reporter killed during the assault. Barry, wounded in the attack, had to be removed through a window before being taken to the hospital. A police officer wounded on the fifth floor, where Barry and Williams were also shot, died a few days later.

In addition to the handover of those convicted of killing his family, Khaalis demanded the film Mohammad: Messenger of God removed from theaters, as well as a meeting with boxer Muhammad Ali.

Ali didn’t come. The stand-off finally ended when ambassadors from Egypt, Pakistan, and Iran appealed to Khaalis’ faith. Thirty-nine hours after the standoff started, Khaalis and his comrades surrendered. Then–U.S. Secretary of State Cyrus Vance later praised the three ambassadors for their efforts ending the siege.

“To these three ambassadors—humanitarians and diplomats in the highest sense—we offer the gratitude of the U.S.,” he said.

Khaalis ultimately received a prison sentence between 41 and 123 years. He died in a federal prison in Butner, N.C., in 2003.