Guardian Angels return to Central Park as crime rises
27 October 2015 Last updated at 20:47 GMT
Back in the 1980s when New York was gripped by violent crime, the Guardian Angels were a familiar sight patrolling the city's streets and subway.
For much of the last decade, however, with a police crackdown sending crime rates falling, there seemed little need for the self-styled "citizen safety patrols", which critics derided as vigilantes.
That changed this summer as New York, along with many other US cities, saw a spike in crime rates - and especially murders - for the first time in years.
Some, including the FBI Director James Comey, have talked about a "Ferguson effect", but the White House insists there is no evidence yet to suggest police officers are failing to fulfil their responsibilities for fear of having their actions second-guessed.
Whatever the cause, the Guardian Angels' founder Curtis Sliwa says his volunteers are responding to calls from residents who no longer feel safe in parts of Central Park. The BBC joined them on patrol.
Produced and filmed by Colm O'Molloy.Edited by Fred O'Connor