Dandora was tense on Friday morning after a police officer allegedly shot a man who was found smoking bhang.
It is also alleged three other young men were shot on Wednesday for the same offence.
The use of marijuana plant and its products is prohibited in Kenya much as there is a debate on whether or not to legalise the same.
Buruburu DCIO Jeremiah Ikiao said the youth in question was a suspected gangster.
"A firearm loaded with some ammunition was recovered from him," Ikiao told The Star.
The shooting brings to light concerns by human rights activists who have complained of rampant cases of extrajudicial killings.
Angry residents lit bonfires on major access roads in the informal settlement following the incident.
They waved placards with inscriptions, "Stop Killing Us". The youths say they have become a prey to the cops.
A number of them complained of harassment by police and haphazard shooting of those who don't bend to the officers' demands.
