Moonstone worked out a plan with the King of Kosmos vizier in Thunderbolts #14 to get the team back to earth. They incite a revolt on Kosmos. The King frees the T-Bolts in order to get their aid. What the King doesn't know is that part of Moonstone's deal with the vizier is for the T-Bolts to kill the king. When Abe (then as Mach-1) couldn't bring himself to deal with the killing blow, Moonstone took control, killing the king. With the king dead, the vizier assumed control thus ensuring the T-bolts transport home, and possible conflict with Kosmos in the future.
Later Abe has to turn himself in for the good of the team on the demand of Hawkeye for him to help the team towards becoming heroes. Since Abe is the only known murderer on the team he turns himself into the custody of the police and is sent to jail. While Abe and Songbird both know that Moonstone Killed the King on Kosmos. Songbird has been keeping this a secret from everyone else for the present time on a promise to Abe. What will happen when Hawkeye finds out what Moonstone did? What will the rest of the team think for that matter? Only time will tell.
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