The investigation into the notorious Croydon Cat Killer will be covered on a BBC documentary which airs tonight.

The Met: Policing London, which airs on BBC One at 9pm, will cover Operation Takahe into the animal killer believed to be responsible for more than 200 deaths.

In an open letter sent to South Norwood Animal Rescue and Liberty (SNARL), Detective Sergeant Andy Collin warned viewers of “upsetting” content including a pixelated image.

A reward of £10,000 is being used as incentive to anyone who delivers information “leading to the arrest of the person/persons responsible”.

Animal charity Peta UK is offering £5,000 with the remaining half being put forward by Outspaced.

Regarding the investigation, DS Collin said: “We are making some progress, but we are not yet in a position to offer any firm updates.”

Tonight’s documentary will be episode four of the series where “a detective investigates a series of cat killings, bringing in a specialist in animal forensic pathology and criminal profiling experts from the National Crime Agency”.

This month there have been reports of animal killings in Wallington, Chatham and Caterham on the Hill which has included a “headless cat” and a fox.

The investigation commenced in November 2015 and DS Collin assured the public that it “remains a very high priority both within the MPS, and particularly at Croydon, where the offences are being investigated from”.

He confirmed that the MPS had “no editorial control of the programme” but he said that having viewed it he believes the show provides “a reasonable balance, it is informative while not seeking to offer a ‘shock value’.”

If you have any information about the case, Operation Takahe can be contacted on 02086490216 or you can report incidents to SNARL on 07961030064.