you are always read your Miranda rights when you are arrested.or at least that is when they are
I should have elaborated and will do so here:
Miranda is required at arrest, but it's not
just at the time of arrest. Miranda is required if the suspect is subject to "custodial interrogation". And that's not based on what you and I might consider 'custody' or 'interrogation'. It is a grey area, and the liminal space between questioning v. interrogation and when 'custody' begins inspires many legal discussions, and by that I mean lots of case law on the subject, many legal articles online, and it's the stuff of motions to exclude/include evidence.
My hope (and I think that this is the case with BK's arrest, just based on the circumstances) is that he was Mirandized immediately. jmo imo and based on tons o' links. here are two to begin:
www.law.cornell.edu