Way to unlock the mission: You get the opportunity to start this side mission along your way out of the sewers under the Burnley district, right after you visit the police morgue in the Scan the corpse in the GCPD morgue mission. Still during your walk along the sewers, you will listen to a police communication concerning the report of the gang fight.
Beginning of the mission
After you return to the Burnley district, you will be able to start completing this optional mission (you can, of course, leave it for later). You need to reach the location where the gang fight took place, in the South-Western part of the Coventry district (the above screenshot).
Deal with the first group of fighting criminals
After you come close to your destination, you should notice two numerous groups of fighting gang members. Do not hope that the criminals will kill each other because you will have to deal with the majority of them anyways. I recommend that you attack from above with high velocity, although you can also debilitate some of the enemies using the concussion detonator or the upgraded glue grenade.
Right after you start fighting, try to jump seamlessly between targets, especially that this is a perfect opportunity to gain a up high multiplier. Watch out for the armored enemies and for the ones armed with knives, do not allow them to deplete Batman's health bar. At the same time, wait for the moment when the access to the shock gloves is unlocked, which will allow you to eliminate the enemies even faster. The last one of the enemies will give up automatically so, you can press the appropriate key/button to interrogate him.
Deal with the second group of fighting enemies
The second gang fight is taking place in the North-Eastern part of the Amusement Mile district, close to the harbor and Penguin's ship.
The overall scheme of action is identical with the previous one so, it is a good idea to attack the enemies from above and, after the main phase of the fight starts, strive for high multipliers and avoid getting hit too frequently. Also in this case, you need to fight until the moment when there is only one hostile left in the battlefield. He will give up and give you the opportunity to interrogate him.
Remain in the location where you have fought the most recent fight and approach the container with chemical weapon stored in it. Activate the evidence scanner and scan the cage right next to the container, which will help you determine Bird's whereabouts.
Reach Bird's staying place
The night club is in the North-Western part of the Coventry district, and its entrance is guarded by more bandits. Just like in the case of the fights that you have recently fought, consider attacking them from above, thanks to which you will eliminate one of them at the outset, or weaken the enemies using the gadgets that you have. For a change,, winning this one is very easy. After all the fights finish, take the entrance to the club [My Alibi - Entrance].
Climb the stairs to the South. After you reach the club's main area, turn left. Go ahead, turn right and jump onto the wall on the right. You are now over the area where Bird and his men are. [Dance Floor].
[New Character Profile: Bird]
Defeat Bird and his men
You can start the fight with Bird and his people in any way you want. They do not own guns and cannot, as a result, reach Batman. Personally, I recommend using the upgraded glue grenade, to hold the boss's most dangerous men, although you can also consider using the grapple, batarangs or the concussion detonator.
After the fighting starts, you should, first of all, note the two enemies wearing very heavy armors, with the green tubes sticking out of their backs. Avoid the charges of this kind of enemies and do not let them grab you. At first, attack then using the cape and a series of quick blows but, only if the shock gloves are available.
A quite useful bit of information is that Bird does not have any unique abilities, nor is he tougher, even though he has a separate health bar. This means that you do not need to pay too much attention to what he is doing and, first of all you should deal with the heavily armored enemies, who have been described above, as well as with the enemies with knives.
Ultimately, you need to eliminate all of the enemies on the dancing floor so, it is best to leave Bird for the very end. After you have depleted his entire health bar, approach him and press the interrogation key/button. This is the end of this quite short, side mission.
[New challenge: Combat Training]
[New Character Trophy: Bird]
[New concept art: My Alibi - Lounge]