Kenyan police have offered a reward of 1 million shillings ($7,700; £5,700) for information leading to the arrest of suspected serial killer Collins Jumaisi Khalusha, more than a year after he escaped from their custody.

Khalusha was the prime suspect in the murder of more than 40 women whose mutilated bodies were discovered in a disused quarry that became a dumpsite in the capital, Nairobi.

Shortly after his arrest, he escaped from custody, along with 12 others, after reportedly cutting through a wire mesh roof and scaling a perimeter wall.

This incident caused widespread outrage, rekindling public backlash over the police's failure to apprehend Khalusha more than a year later.

Many Kenyans have questioned how he could have escaped from what is regarded as one of the most secure police stations, situated near both the US embassy and the UN offices in Nairobi.

Khalid Hussein, an activist closely following the case, stated that police are not serious about addressing the murders of the women identified as being aged between 18 and 30. He claimed that some bodies remain in the quarry pits, rotting.

Mr. Hussein believes the Directorate of Criminal Investigations (DCI) announced the reward following a documentary aired by Citizen TV, highlighting police inaction.

As usual, they feel embarrassed, they think they should do something and they react and they say one million shillings reward. Absolutely useless, the activist expressed.

Contacted by the BBC, police spokesman Michael Muchiri directed questions to the DCI, which had previously mentioned the complexities of that matter while assuring they are on track to resolving it.

The DCI announced via X that the 1 million shillings reward would be granted to anyone providing credible information leading to Khalusha's re-arrest.

Police had also offered a reward last year but did not specify the amount at that time.

Last year, several policemen were arrested for allegedly aiding Khalusha's escape, though they were later released on bail.

Public frustration continues regarding the police's failure to detect the bodies left just 100 meters from their station.

Khalusha reportedly confessed to his crimes, but his lawyer later stated that he had been tortured into confession.

At the time of his initial arrest, DCI chief Mohamed Amin stated, It is crystallising that we are dealing with a serial killer, a psychopathic serial killer who has no respect for human life, who has no respect and dignity.

Initially, Khalusha was set to face murder charges in court before his disappearance.

Last month, Interior Minister Kipchumba Murkomen described the escape as regrettable and a sad story, expressing hopes for his eventual arrest.