A special forensic team has been dispatched to River Yala in a bid to probe the 19 unclaimed bodies.
In a statement on Wednesday, Police spokesman Bruno Shioso said the bodies had been dumped in the river for the past two years.
The bodies were found in sacks, some tied up and others mutilated.
He denied claims that the 19 bodies were dumped at once.
"Despite an appeal from the police, no one has come forward to claim the bodies," he said.
Shioso appealed to anyone with information to come forward to aid in the investigations.
Journalists who visited the river said there were more bodies floating on, and lying by the River.
Some residents who have been actively documenting the recoveries insist the 20 bodies were recovered from July last year.
Some families with missing loved ones have started reporting to Yala police station and the mortuary hoping to identify the bodies.
A diver said he helped retrieve four bodies this month.
HAKI Africa wrote to DPP Noordin Haji requesting his intervention over the River Yala bodies saga.
There is an ongoing public debate over the 19 bodies.
A section of Kenyans took to social media to raise concern over the reports, as they asked Inspector General of Police Hillary Mutyambai to open investigations into the matter.
