I am still trying to connect the dots on how the Death Gun Incident is connected to Laughing Coffins. Most of the real names you heard on the Death Gun page are all members of Laughing Coffins.
In Muder in the Safe Zone Kirito told Asuna while they were having dinner that players were abusing the duel system and doing player killing, but their meal was interrupted when Cayne hung himself. (Not realy it was a plot to lure out Schmitt and Grimlock and expose the Laughing Coffins.)
They did not know who was behind it since you can not kill another player in a safe zone unless you challenge them to a duel and no one had the winner icon.
After an investigation it was found out the Laughing Coffins were involved and the Clearers were sent to raid their headquarters.
All of the Laughing Coffins members were killed but Poh, XaXa, Johnny Black, Lux, and Kuradeel escaped.
Heathcliff, Kirito, and Asuna captured XaXa,and Johnny Black and sent them to prison until they returned to the real world and were sent to a real jail.
Lux defected and had her tattoo removed.
Poh managed to stay below the radar but Kuradeel infiltrated the Knights of the Blood Oath and pretended to be Asuna's bodyguard.
During a training mission Kuradeel killed two members of the Knights of the Blood Oath by poisoning them and than he took off his cloak to inform them that he was a Coffin.
Kirito and Asuna killed him and that was thought to be the last they saw of the Laughing Coffins they were wrong.
A year later GGO came out and two Laughing Coffins members joined up and brought Spiegel with them. Their target was Sinon their neighbor.
The plan was XaXa would enter the game as Death Gun and shoot their avatars then Johnny Black, and Spiegel would kill the users.
The plan almost backfired. Spiegel had his licence suspended and the only one allowed to drive a bike was Johnny Black.
There was another problem Pale Rider and Garett lived in the same apartment complex but XeXeed, Sinon, Tarako, Asuna, and Kirito lived across town and were in a secured area.
Sinon's apartment was fitted with the older locks making it esay for Spiegel to make a copy of her keys. He broke into her apartment at the time when Kirito won GGO and attempted to kill her.
Kirito logged off got on his bike and raced to Sinon's apartment and stopped Spiegel and held him until cyber security arrived and arrested him. Poh is still at large.