how did ikemefuna die?

I think Okonkwo kills him? I may be wrong, I don't have my book near me.

the clan decides to kill him and okonkwo participates in it but it doesn't tell whether he himself killed him or not

He was advised to stay out of the killing, but during the execution Ikemefuna runs to Okonkwo crying "Father, they have killed me!" or something then Okonkwo, being scared to be seen as a coward, draws his matchet and kills Ikemefuna.

One of the men following ikemefuna cleared his throat and ikemefuna looked back, and the man growled at him to go on and not stand looking back. And so Ikemefuna did. And after a while  the same man drew up and raised his matches. Okonkwo looked away. He heard the blow. The pot fell and broke in the sand. He heard ikemefuna cry. My father, they have killed me! As he ran towards him, then Okonkwo drew his matches and cut ikemefuna  down. Okonkwo was afraid of being thought weak.