To give credit where due, likely a Muslim man.
An African with the first name of Abdul is for sure Muslim, at least by birth/identification anyway. In fact, I think even among Arab/African Christians, the name Abdul is never used as a first name, so his first name is certainly a giveaway that he is Muslim by birth.
But the key part is he is Muslim by birth, and apparently, someone who was not raised on full throttled islam, and taught all the defining characteristics of islam in its purest, harshest and most uncompromising forms, i.e. cowardice, lack of empathy for all non-muslims, sociopathy and homicidal rage. He seems to have much more in common with devout African Christians than he does with fanatical Muslims like you’d find in Somalia or Sudan. He was likely raised to be a traditional African first and foremost. The Al Shahaab allied monsters who launched this attack on the first place are a much more typical example of what you get when one is raised to care about their Islamic identity above everything else.