A 35-year-old woman has died after being knocked down by a scrambler motorbike in Colin Glen Forest Park.
Police said in a statement on Twitter that mother of three Valerie Armstrong passed away peacefully surrounded by her family.
Two youths were arrested after the collision in the Dunmurry area of greater Belfast around 6pm on Tuesday.
The PSNI added: "A 17-year-old male is due in Belfast Magistrates Court on Thursday charged in connection with the incident. A 15-year-old male has been released on police bail."
West Belfast Assembly member Jennifer McCann said the local community was in shock.
"Many people will have been out enjoying the sunshine in the park and it is shocking to think that something like this could happen," said the Sinn Fein representative.
"My thoughts are with the family and friends of this woman."
Police have appealed for witnesses to come forward.
Earlier Superintendent Melanie Jones said: "This is an active and live investigation, I am appealing for any members of the public who were in the park yesterday evening and saw any off-road bikes being used at around 6pm in the run up to this tragic collision to please come forward with an information that you may hold.
"I want to take this opportunity to remind the public that while the use of such motorised vehicles as a leisure activity can appear to be both exciting and fun, if used inappropriately, can be dangerous and against the law.
"We are aware of concerns in the local community about people riding scramblers and quads recklessly, especially in public parks, and I want to assure the public that we will take action to curb the nuisance and dangers associated with the use of off-road scramblers and quads in public areas.
"Some scramblers do not comply with Vehicle Safety Standards and are therefore restricted to ‘off-road’ use only because they do not comply with the necessary legislation for use on a public road or in a public place. This does not mean they can be driven anywhere ‘off-road’.
"These vehicles can only be used on private land where the landowner has given permission and should not be used on pavements, roads, public property or parks; this includes green grass areas and public paths. Riders must be aware of the minimum requirements by law, such as insurance and safety equipment that must be complied with in order to drive these vehicles legally.
"If vehicles are designed for use on roads, they should have the appropriate equipment fitted such as lights and number plates and the driver/rider should be the holder of a suitable driving licence and insurance. If vehicles are not designed for the road and not insured, they can only be used on private lands with the permission of the landowner."
Superintendent Jones added: "I would urge people to consider others in the areas where these vehicles are being used. Parents too are asked to play their part by considering how their children use these vehicles. Police also have the power to seize these vehicles. It is important that people recognise that this is a real possibility and has happened before.
"Police will enforce the necessary legislation in an effort to ensure public safety. As we have seen last night in Colin Glen Park these vehicles can be very dangerous if not used legally and in a controlled environment.
"I would appeal to anyone who witnesses this type of activity in the area or who has any information to contact their local police on 101. Or, if someone would prefer to provide information without giving their details, they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111."