Mr Anyiam-Osigwe died at a hospital in Lagos on Sunday from fatal injuries sustained during the attack.
He was coordinator of the Anyiam-Osigwe Group and secretary to the Supervisory Board.
In a message posted on Facebook on Thursday, Peace expressed her anger while extoling her brother’s sterling qualities.
She described her brother, who was a pillar of support for AMAA, as a leader and true gentleman.
Her full statement reads:
“I am angry so angry about the brutal death of my brother Michael Anyiam-Osigwe, he walked with the poise of a leader. The embodiment of peace coupled with the eloquence of a true gentleman, he who was the personification of genius.
“Like your father who was the extraordinary form of man, you understand where others were ignorant the reality of the world and its truth were your knowledge base.
“Michael, you were, you are, and you are still and will forever remain one of the greatest to this country and the world at large. You have not left, you have transcended. Remember, character is personality and personality outlives death.”