Is a confession always admissible?
No. Several independent challenges exist.
Voluntariness. A statement must be the product of free will rather than an overborne one, assessed on the totality of the circumstances — length of questioning, deprivation of sleep, food, or medication, the person's age, intelligence, and mental condition, and any threats or promises made.
Miranda compliance. Whether warnings were required, whether they were given, and whether the waiver was knowing, intelligent, and voluntary.
Invocation. Whether the person invoked and whether officers honored it.
Corpus delicti. Florida generally requires independent evidence that a crime occurred before a confession can be used to prove it — a confession alone isn't enough.
Recording matters enormously to all of this. Where the interrogation was recorded in full, these questions have answers. Where only part was recorded, or only a written summary exists, what happened before the recording started becomes its own issue.
Ask whether the whole interview was recorded. What's missing is often the point. ---
Talk to an Attorney — Free
An answer on a page isn't the same as advice about your case. Talk to an attorney who handles these matters on the Treasure Coast — free and confidential.