Mystery Killer

Mystery Killer is a main story mission in GTA Advance, given by Cisco.

It's the 34° GTA Advance mission in chronological order, and it takes place in Shoreside Vale.

In Shoreside Vale, Mike receives conflicting pager messages. One invites him to Wichita Gardens for a job, signed "XOX". The other, from Cisco, warns him it's a trap and to meet at the airport instead.
In the first option, Mike opts to go to Wichita Gardens, where he is ambushed but manages to survive. After the ambush, he heads to Cisco's headquarters at the airport. Cisco confirms that he had warned Mike about the trap and offers to help find the assassin responsible for the bomber's death. Both are puzzled by the assassin's apparent knowledge of Mike.
In the second option, Mike decides to meet Cisco at the airport first. Cisco warns him of the ambush, offering some backup. Despite the warning, Mike proceeds to Wichita Gardens. He survives the planned ambush there, and then returns to Cisco. Cisco expresses hope that his men were helpful, even though they were largely ineffective. Again, both are intrigued by how much the assassin seems to know about Mike. Mike is appreciative of the backup but maintains a cautious distance from Cisco moving forward.