Just before the call cut off, she heard Trayvon Martin say, “Get off. Get off.”

[Tommy_Carcetti]

88. This may be helpful: Fla. Stat. 90.804

90.804 Hearsay exceptions; declarant unavailable.—

(1) DEFINITION OF UNAVAILABILITY.—“Unavailability as a witness” means that the declarant:
(a) Is exempted by a ruling of a court on the ground of privilege from testifying concerning the subject matter of the declarant’s statement;
(b) Persists in refusing to testify concerning the subject matter of the declarant’s statement despite an order of the court to do so;
(c) Has suffered a lack of memory of the subject matter of his or her statement so as to destroy the declarant’s effectiveness as a witness during the trial;
(d) Is unable to be present or to testify at the hearing because of death or because of then-existing physical or mental illness or infirmity; or
(e) Is absent from the hearing, and the proponent of a statement has been unable to procure the declarant’s attendance or testimony by process or other reasonable means.
However, a declarant is not unavailable as a witness if such exemption, refusal, claim of lack of memory, inability to be present, or absence is due to the procurement or wrongdoing of the party who is the proponent of his or her statement in preventing the witness from attending or testifying.

(2) HEARSAY EXCEPTIONS.—The following are not excluded under s. 90.802, provided that the declarant is unavailable as a witness:
(a) Former testimony.—Testimony given as a witness at another hearing of the same or a different proceeding, or in a deposition taken in compliance with law in the course of the same or another proceeding, if the party against whom the testimony is now offered, or, in a civil action or proceeding, a predecessor in interest, had an opportunity and similar motive to develop the testimony by direct, cross, or redirect examination.
(b) Statement under belief of impending death.—In a civil or criminal trial, a statement made by a declarant while reasonably believing that his or her death was imminent, concerning the physical cause or instrumentalities of what the declarant believed to be impending death or the circumstances surrounding impending death.
(c) Statement against interest.—A statement which, at the time of its making, was so far contrary to the declarant’s pecuniary or proprietary interest or tended to subject the declarant to liability or to render invalid a claim by the declarant against another, so that a person in the declarant’s position would not have made the statement unless he or she believed it to be true. A statement tending to expose the declarant to criminal liability and offered to exculpate the accused is inadmissible, unless corroborating circumstances show the trustworthiness of the statement.
(d) Statement of personal or family history.—A statement concerning the declarant’s own birth, adoption, marriage, divorce, parentage, ancestry, or other similar fact of personal or family history, including relationship by blood, adoption, or marriage, even though the declarant had no means of acquiring personal knowledge of the matter stated.
(e) Statement by deceased or ill declarant similar to one previously admitted.—In an action or proceeding brought against the personal representative, heir at law, assignee, legatee, devisee, or survivor of a deceased person, or against a trustee of a trust created by a deceased person, or against the assignee, committee, or guardian of a mentally incompetent person, when a declarant is unavailable as provided in paragraph (1)(d), a written or oral statement made regarding the same subject matter as another statement made by the declarant that has previously been offered by an adverse party and admitted in evidence.


http://www.flsenate.gov/Laws/Statutes/2010/90.804

I think the prosecution has a good argument to get them in. Of course, credibility of the hearsay witness will still be attacked, naturally, by the defense.