Is a warrantless arrest reasonable under the Fourth Amendment?

" [A] warrantless arrest by a law [enforcement] officer is reasonable under the Fourth Amendment where there is probable cause to believe that a criminal offense has been or is being committed. " ( People v. Thompson (2006) 38 Cal.4th 811, 817, 43 Cal.Rptr.3d 750, 135 P.3d 3.) " Probable cause exists when the facts known to the arresting officer would persuade someone of "reasonable caution" that the person to be arrested has committed

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a crime. " ( Id. at p. 818, 43 Cal.Rptr.3d 750, 135 P.3d 3.) Where an officer makes a warrantless arrest based on a belief they have probable cause to do so, "the officer must testify to the facts or information known to him on which his belief is based" because "the court and not the officer must make the determination whether the officers belief is based upon reasonable cause." ( People v. Boyles (1955) 45 Cal.2d 652, 656, 290 P.2d 535.) The prosecution bears the burden of proving the reasonableness of a warrantless arrest. ( People v. Williams (1999) 20 Cal.4th 119, 130, 83 Cal.Rptr.2d 275, 973 P.2d 52.)