By Noel Mwakugu
BBC News, Nairobi
As Kenya's opposition protests enter a third day, people are increasingly questioning the actions of the police, who are accused of shooting dead protesters.
The killings have sparked outrage across the country.
On Thursday, human rights activist Okia Omtata chained himself to the barriers of the Nairobi police headquarters and, as bystanders watched, clutched a rosary chanting: "You are killing people in this country. That is wrong.
"The sanctity of life must be protected."
He was soon arrested.
Earlier, television footage had suggested a policeman in Kisumu may have shot dead in cold blood an unarmed man taking part in opposition protests against last month's disputed elections.
The protester was making faces at the anti-riot unit when an officer approached him and fired his rifle.
The young man fell down and the policeman is shown kicking the prostrate man in the back.
The protester was later pronounced dead.
In defence, police spokesman Eric Kiraithe insists officers are well aware that they are dealing with innocent people being "used by politicians".
"Some are drunk on alcohol and others are high on drugs and it is obvious they are innocent, so we are not using excessive force to disperse them," he said.
The police chief in Kisumu said officers had disobeyed orders to only use tear gas and truncheons and were investigating the incident.
However, allegations of excessive force by Kenya's police are not new.
Late last year they were accused of extrajudicial killings during the infamous crackdown on suspected members of the outlawed Mungiki sect in Nairobi and Central Province.
At least 500 people died then. More than 600 have died in the election protests.
The government-sponsored Kenya National Commission for Human Rights accused the force of executing large numbers of youths based on suspicion they were members of the secret sect.
Allegations of excessive force by Kenya's police are not new
Many accusations of brutality against civilians are aimed at the dreaded paramilitary General Service Unit (GSU).
Many Kenyans know the unit by its Swahili acronym, FFU. They half-jokingly say this stands for Fanya Fujo Uone ("Mess around and see what we will do to you").
Members of the unit have undergone special training to deal with any threat to national security and, unlike the regular police, they rarely mingle with the public.
This, it is argued, makes them insensitive and brutal during their operations.
In the past, they have been accused of raping women just to instil fear during operations.
During the 24-year rule of former President Daniel arap Moi, this was his most trusted unit among the security forces.
Onyango Oloo of the Sankara Centre, a local human rights lobby group, says the police have often been used by the political elite to unleash brutality and terror on its opponents.
"This goes back to the colonial times but certainly it has been part and parcel of how the state has dealt with the opposition - by crude brutality," says Mr Oloo, a former political prisoner.
In Kisumu, an opposition stronghold, residents have told the BBC that policemen have been firing indiscriminately at rioters in the suburbs.
In the first round of unrest, I saw more than 40 bodies in the city's mortuary.
Most had bullet wounds. Again, residents blamed the police, who denied responsibility for any deaths.
Residents of Nairobi's Kibera and Mathare slums have also accused the police of firing indiscriminately.
Human rights activists allege that the officers are responding to a shoot-to-kill order issued by former Internal Security Minister John Michuki.
Mr Oloo says the actions of policemen in using live ammunition on unarmed protesters is illegal under Kenyan law.
And it is emerging that there is growing discontent among officers at civilian deaths.
There have been unconfirmed reports that some officers in Kisumu, where most of the shooting has taken place, have declined to follow orders to shoot at the public.
Kenyans are questioning police actions when protests are peaceful
Observers argue a good number of police are sympathetic to the opposition.
"I am convinced among them there are those who do not approve of what is happening and if they were asked to choose they would not rein in the protesters," Mr Oloo says.
He says it is wrong to believe individual policemen have brutality ingrained in them.
But it is unlikely the police force as a whole would refuse to take orders from the government.
Members of the force are recruited from across Kenya's 43 ethnic groups.
Although some of top commanders have been seen aligning themselves with the ruling elite, political tensions have rarely been displayed among lower cadres.
But Ben Rawlence, a researcher with Human Rights Watch, says an inquest should be opened to address the killings across Kenya.
"People have been killed under circumstances that are not justified and the police must be held accountable," says Mr Rawlence.