Complex sentence: He was a close friend of Saïd and Chérif Kouachi, the gunmen in the "Charlie Hebdo" shooting, to which both of Coulibaly's shootings were connected, and said he synchronized his attacks with the Kouachi brothers.
Split into simpler sentences: He was a close friend of Saïd and Chérif Kouachi, the gunmen in the "Charlie Hebdo" shooting, to which both of Coulibaly's shootings were connected. He said he synchronized his attacks with the Kouachi brothers.