Here's the thing though:

upon reasonable and probable grounds of suspicion.

The legal standard as it reads to me is that you do not have to have 100% proof of a felony, just a reasonable suspicion that a felony was committed. Being in a neighborhood with a recent history of burglaries, seeing a man entering a house without authorization who matches the description of a prior burglary suspect and flees when spotted... I think that it would be reasonable to suspect he burglarized that dwelling - and burglary is a felony.

Here's the thing though:

upon reasonable and probable grounds of suspicion.

The legal standard as it reads to me is that you do not have to have 100% proof of a felony, just a reasonable suspicion that a felony was committed. Being in a neighborhood with a recent history of burglaries, seeing a man entering a house without authorization who matches the description of a prior burglary suspect... I think that it would be reasonable to suspect he burglarized that dwelling - and burglary is a felony.