Is a waiver of the Miranda waiver not voluntary nor knowing, but was obtained by coercive police tactics?

Serna argues his waiver of rights was neither voluntary nor knowing, because it was obtained by coercive police tactics. The People bear the burden to establish by a preponderance of the evidence that a defendant's statements were voluntarily obtained. (People v. Guerra (2006) 37 Cal.4th 1067, 1093, overruled on other grounds in People v. Rundle (2008) 43 Cal.4th 76.) A statement obtained from "[p]sychological coercion is equally likely to result in involuntary statements, and thus is also forbidden." (Collazo v. Estelle (9th Cir. 1991) 940 F.2d 411, 416.) Serna opines the psychological coercion he endured stemmed from his terrifying arrest involving a police canine, his nine-hour detention before he was interrogated, and the stress he endured from not knowing why he was in police custody. Serna also points out that he was handcuffed during his detention and was only released from the handcuffs after Miranda warnings were given.