Well, depending on what you read and which sources you believe.
The DHQ, for example,
says it cannot confirm the death of Shekau, and referred to media reports claiming Shekau had been killed as "speculation."
Military sources, speaking with Vanguard however, have a long (and remarkably fantastic) narrative about how they killed the sect leader. (
Read the story here)
Sahara Reporters, however, will have none of it. First they have said Shekau died a year ago and the man killed is actually called Bashir Mohammed (
read this here), and that the leader of the Boko Haram sect is alive and well (
click here to read). A bit conflicting, if you ask me.
Meanwhile Cameroon and Nigeria are in their own little bit of controversy over which country actually killed Shekau. Cameroon released a statement and photos stating that it killed Shekau during an airstrike on his hideout.
Nigeria, however, says it killed Shekau in Konduga, but as yet there is no photo evidence to support Nigeria's claim (
read all about that here)
Personally, I believe right now we can only speculate, and we may never know the truth.