Call to probe deaths during mass protests.
Kenyan officials have been asked to rein in police officers accused of using excessive force during the election period.
“Kenya has to put an end to the culture of election-related violence, unlawful killings by police and impunity for abusive officers,” said Mr Otsieno Namwaya, the Africa researcher at the Human Rights Watch (HRW).
Mr Namwaya also called on the authorities to investigate scores of deaths that occurred during mass protests in the recent past.
“President Uhuru Kenyatta and other government officials should condemn ongoing killings and ensure that there are thorough and independent investigations into such killings and the role of any armed groups in the violence,” he said.
In October, HRW and Amnesty International documented at least 67 killings, most by gunshot, during protests by opposition supporters after the August 8 election.
In a recent statement, HRW indicated that a series of protests and clashes between police and opposition supporters last week left several dead.
Police spokesman George Kinoti said members of the public lynched five people on November 17 for looting before the officials arrived. He promised to investigate the deaths.
“The protests and clashes continued in opposition strongholds in Nairobi and western Kenya following the Supreme Court decision on November 20, affirming President Uhuru Kenyatta’s re-election,” the statement read.
The rights group pointed out that the latest round of violence started after the authorities deployed police who used teargas and water cannons to break up large crowds cheering Mr Odinga.
On November 19, opposition supporters engaged police in running battles in some parts of Nairobi as they protested the killing of five people by unidentified attackers.
Neighbours who witnessed one of the attacks told Human Rights Watch they believed the attackers were members of an outlawed group.
Nairobi police boss Japheth Koome dismissed the allegations and promised to launch investigations on the killings.
Mr Namwaya, however, noted that the authorities have failed to investigate similar attacks or to hold anyone responsible for the killings by police since the August 8 election.
-Reported by Victor Raballa.