The call to prayer echoes across Besiktas district.
This evening the imam will pray for Senol Sagman, a young man shot dead by troops as he and thousands of others poured onto the streets to oppose the attempted putsch.
Mustafa Gülenc, tall, bulky but unassertive man, had been his friend since childhood and ran a catering business with him
He was beside Sagman when he died.
“We went out into the streets, the soldiers were in front of us, we were saying ‘Allahu Akbar’, ‘Allahu Akbar’, Gülenc recalls. We told the soldiers ‘Don’t fire on us. A Muslim cannot kill a Muslim!’ They said ‘Don’t say Allahu Akbar!’ First they shot in the air, then they shot at us. I lay down and when I got up I saw that my friend was dead.”
Like most Turks, Gülenc has no kind words for the soldiers who took part in the coup and killed his friend.
“They are just terrorists," he says. "They are terrorists in uniform.”
Both men were supporters of President Recep Tayyip Erdogan’s Justice and Development Party (AKP) and local AKP leaders are present at the ceremony.
Although European leaders have expressed fears that the government's response to the coup could impinge on the democracy they claim to defend, Gülenc is confident the thousands who have been sacked or detained will receive the treatment they deserve.
“The state will decide," he says. "The people governing us know best. This is a democratic country, the government will know what to do.”
Two giant wreaths stand by the graveyard next to the mosque.
Sagman’s friends and political associates clearly mean to ensure that his memory survives.