What is the test for establishing a coercive atmosphere in a criminal investigation?

whether the person voluntarily agreed to an interview; whether the express purpose of the interview was to question the person as a witness or a suspect; . . . whether police informed the person that he or she was under arrest or in custody; whether they informed the person that he or she was free to terminate the interview and leave at any time and/or whether the person's conduct indicated an awareness of such freedom; whether there were restrictions on the person's freedom of movement during the interview; how long the interrogation lasted; how many police officers participated; whether they dominated and controlled the course of the interrogation; whether they manifested a belief that the person was culpable and they had evidence to prove it; whether the police were aggressive, confrontational, and/or accusatory; whether the police used interrogation techniques to pressure the suspect; and whether the person was arrested at the end of the interrogation." (People v. Aguilera (1996) 51 Cal.App.4th 1151, 1162.) In considering the facts surrounding the questioning, "we look at the interplay and combined effect of all the circumstances to determine whether on balance they created a coercive atmosphere such that a reasonable person would have experienced a restraint tantamount to an arrest." (Ibid.)