The term "fresh pursuit" as used in this act shall include fresh pursuit as defined by the common law, and also the pursuit of a person who has committed a felony or who is reasonably suspected of having committed a felony. It shall also include the pursuit of a person suspected of having committed a supposed felony, though no felony has actually been committed, if there is reasonable ground for believing that a felony has been committed. Fresh pursuit as used herein shall not necessarily imply instant pursuit, but pursuit without unreasonable delay.