Nairobi's gang killers have resurfaced again.

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The  Saigon Purnisher and Hessy wa Dandora are among 'police officers' who use social media specifically Facebook, to warn suspects before eliminating them if they don't change.

It is alleged the group is made up of highly trained police officers who don't arrest suspects, they warn and give suspects like a week or so to change from wrong ways including robbery with violence, among others, and if the suspect ignores the warning from them, they put them on their shoot-to-kill radar.

The group had gone mute quite for a number of months. Their actions were not being shared on Facebook like they used to, until late last month when they warned three suspects before killing them a few days later.

"These 3 dogs ndio huterorize huruma las Vega metameta na hapo down kwa bridge wahame ama wajiandae kupandwa,hakuna vile wataendelea kudunga raia visu na kujigamba wao ni immortal!!!don't reform just continue with your league tutaona who is the champ nonsense, (The three terrorize Huruma residents using knives, I warn them)," posted Saigon Purnisher.

After sounding the above warning, it only took less than a week for the undercover officers to fell the suspects. They shared shot-killed suspects with a caption asking people to keep calm and not to question them.

They also used the chance to warn five more suspects who were still wanted on their radar.

"Na sitaki maswali wacha mbwa zikufe, sikio la kufa halisikii dawa two down five to come," reads part of a Facebook post of the group