Civil society representatives, political leaders and citizens were gathered at the stadium, waving the national flag, praying on the pitch and chanting, calling on military junta leader Moussa Dadis Camara not to run for the presidency, when soldiers gunned down and raped demonstrators.
Diallo's father and other relatives have come from their village in Dalaba, about 360km from Conakry, to search for him. They have been to military camps, hospitals and morgues in the city, but have found no record or other sign of him.
The Red Cross continues to receive calls from families seeking relatives missing since 28 September, according to the UN in Guinea.
Children in the Diallo household wonder where their big brother is. An aunt showed IRIN the closed door of the young man's now-unused room in the extended family home in Conakry and kept referring to him in past tense.
"He was a gentle, respectful young man and he was always kind with the children – the children in the house ask where he is.
"All we know is that he was with a friend at the stadium that day – not a trace since then.
"On 1 October, the day before the authorities were going to bring bodies out of the morgue for identification, his older brother had to call their mother, who is still in the village. He told her Abdoulaye was at the stadium and we have not heard from him since.
"We are in despair but we continue to search. We have a bit of hope, since we do not have proof that he is dead.
"The situation in Guinea is extremely difficult today – there is no security.
"We go through our days in the household living in worry. I really don't have the words to express what we're going through."
ic/np/he
This article was produced by IRIN News while it was part of the United Nations Office for the Coordination of Humanitarian Affairs. Please send queries on copyright or liability to the UN. For more information: https://shop.un.org/rights-permissions