Police in Kenya have recovered a head believed to be that of a 20-year-old student who was murdered and dismembered in the capital, Nairobi, earlier this month.

The mutilated remains of Rita Waeni were discovered disposed in trash bags at a short-term rental apartment on 14 January, but her head, along with her phone and other personal items, were missing.

Police are yet to confirm whether the head, which was recovered on Sunday in Kiambaa Dam, nearly 15km (nine miles) away from the murder scene, is Ms Waeni's.

"It was decomposing. It was wrapped in a purple blouse and with it, we also found a stone. We believe that it was there so that it could sink," Kiambaa police commander Pius Mwanthi was quoted as saying by the Kenyans news website.

Police also retrieved Ms Waeni's phone and some of her other missing items from the dam.

Ms Waeni's killing continues to shock Kenyans, particularly because of the brutality with which it was done.

"This is the first time I have come across such an incident. I have never come across such in my forensic life," Kenya's chief government pathologist Johansen Oduor said on Friday.

Ms Waeni's family said last week that the killer demanded a ransom of 500,000 Kenyan shillings ($3,100; £2,400) to release her, even after he had killed her.

A suspect is in custody over her killing.