It is understood a number of people were in the garden at the time.
There are no reports of anyone injured.
McKee was murdered early on Good Friday morning in the Creggan in Derry.
Gardaí believe a local gang feud in the area is the motive behind the shooting.
The incident happened shortly after 11.15pm at Poppintree Crescent, Ballymun last night.
The investigation is centering on a well-known north Dublin criminal.