The mourners gathered early Wednesday morning. They knew the authorities would not let the former Iranian opposition leader be buried at midday, when his funeral would attract even more followers.
Ezzatollah Sahabi, 81, had been among the leaders of Iran's 1979 Islamic Revolution and a member of its first government, but later fell out with those in power. He spent his last decades as a dissident, in and out of prison.
Sahabi's daughter Haleh, 57, followed in his political footsteps. A women's rights campaigner, she joined the "Green" movement that held major protests in Tehran over allegations of fraud in the June 2009 election that kept President Mahmoud Ahmadinejad in power.
Along with other activists associated with the 2009 demonstrations, Haleh Sahabi had been sentenced to prison but was released last month on furlough because her father had slipped into a coma. He died late Tuesday.
She and her family had to negotiate the time of Sahabi's funeral with authorities, who are leery of any excuse for new protests. Security forces wanted the burial to take place at 3 a.m. but the family argued and a compromise was struck for it to be held several hours later.
It was 7 a.m. when mourners gathered at the entrance to the cemetery for war veterans in the hills of northern Tehran.
Haleh Sahabi had driven with her father's coffin from the family home. Riot police watching the procession refused to let the mourners carry the coffin on foot, witnesses said.
She argued with police, insisting that it was the family's right to accompany their loved one to his burying place. There was a scuffle, and she fainted. She was rushed to a hospital, but died of a heart attack on the way, family and close friends said.
Mourners continued to the burial site, not knowing she had died.
Plainclothes agents and riot police surrounded the area, but for an instant, a few voices cried out, "Death to the dictator." Several people were whisked away.
"Since last night, we could not sleep a wink as the security and police agents called us and summoned us to force us, first politely and later impolitely, to finish up the funeral and burial before dawn," one relative said as he watched a small crowd pray by Ezzatollah Sahabi's grave. The relative asked not to be identified, saying he could be arrested for his comments.
The funeral was to have been presided over by the son of a late dissident cleric and onetime heir to former Iranian leader Ayatollah Ruhollah Khomeini. But he missed it, evidently fatigued from the late night vigil, confused by the presence of the security men and concerned about rumors that his own son had been arrested. He wandered the plots in a daze.
Late in the day, Haleh Sahabi's body was brought to the cemetery. This time, a smaller crowd had gathered. Police watched as she was placed in a grave next to her father's and the mourners quietly dispersed.
Times staff writer Parker reported from Baghdad and special correspondent Mostaghim from Tehran.