Diakite was the lieutenant widely cited as being involved in the September 28 crackdown.
There have been consistent rumours of deep divisions within the army since Camara seized power in a military-led coup 11 months ago.
Cherif said that Camara had left the main military camp where he lives and works and went to a military camp in downtown Conakry where the shooting occurred.
The former French colony has been tense since presidential guard troops opened fire on pro-democracy demonstrators on September 28.
Al Jazeera's Yvonne Ndege, reporting from Nairobi, said: "The atmosphere in Guinea's capital Conakry is extremely tense according to our sources on the ground.
"Some sort of dispute broke out between the junta leader, Camara, and his chief personal security guard over whether this chief would be arrested in the aftermath of the September 28 massacre.
"Witnesses say that they did see a military helicopter taking somebody or something to a military hospital," she said.
The UN and rights groups have said at least 150 people were killed. The government has said 56 people died.
A United Nations commission is investigating the massacre.
Guinea's military rulers have meanwhile set up their own 31-member independent commission of inquiry into the massacre, which Kabine Komara, the prime minister, has said would work in tandem with the UN probe.
International pressure is growing on Camara, who seized power in a coup in December last year.
The International Criminal Court plans to hold a preliminary inquiry to determine if war crimes had been committed.
The 15-nation Economic Community of West African States (Ecowas) have agreed on weapons sanctions against the military government.