In what circumstances will the police force coerce a defendant to make false admissions in a felony-murder case?

Here, defendant argues the detectives coerced him to make false admissions by (1) falsely implying to defendant and his brother that defendant would not get much jail time if he admitted the shooting was an accident (conveying a false distinction between accident and cold-blooded murder in this felony-murder case and impliedly offering leniency), and (2) threatening to put "everybody" in jail. Although defendant cites authority that a threat to arrest a near relative may be coercive (e.g., People v. Matlock (1959) 51 Cal.2d 682, 697), defendant does not assert or cite evidence that the police threatened to put any of his relatives in jail. Rather, he just says the police threatened to jail his friends who were potential accomplices.