Major FL Court Discusses When Co-Defendant Testimony Warrants a Mistrial

April 10, 2026 Don Pumphrey, Jr. Criminal Defense Social Share

Florida’s 6th District Court of Appeal ruled that the defendant was not entitled to a mistrial after a co-defendant testified he and the defendant texted about committing an additional, uncharged robbery. However, one judge disagreed.

CASE: Quesada v. State, — So.3d — (Fla. 6th DCA 2026)

Charge(s): Conspiracy to Commit Robbery with a Firearm, Attempted Robbery, Attempted Felony Murder

Outcome: Convictions AFFIRMED – Quesada was not entitled to a mistrial after testimony from the co-defendant implicated Quesada in planning another, uncharged robbery.

Severance in Florida

In Florida and throughout the United States, defendants at criminal trials are guaranteed the right to due process and a fair trial – under the Florida and U.S. Constitutions. U.S. Const. amend. XIV, § 1; Fla. Const. art. I, § 9.

To ensure a defendant’s liberty is protected, it is sometimes necessary to move to sever charges or co-defendants. Severance may occur when either of the following are true:

• Defendants that were initially going to be tried together (e.g. for an underlying crime that they are accused of perpetrating) are “separated,” resulting in the defendants being tried individually (e.g. severance of co-defendants)
• The defendant was charged with multiple criminal offenses, and to ensure that the nature of one charge does not lead to an “automatic” finding of guilt on the other charges (e.g. reduction of burden of proof due to jury bias), separate trials are ordered for each of the charges (e.g. severance of charges)

Florida’s courts give the trial judge discretion to grant or deny motions for severance – but advise that severance motions should be granted “liberally” if there is a chance that the defendant will be prejudiced by continued joinder. State v. Vazquez, 419 So.2d 1088, 1091 (Fla. 1982)

Notably, a defendant is NOT automatically entitled to severance just because severance may be more tactically advantageous. Severance of charges or co-defendants is to occur only when it’s necessary to ensure a fair determination of guilt or innocence for one or more co-defendants (or on each of the charges, per Florida Rule of Criminal Procedure 3.152).

The first type of severance – severance of co-defendants – is likely to occur if either of the following are true:

• The evidence sought to be admitted at trial applies only to one co-defendant, but may improperly influence the jury as to the charge against the other defendant(s) (Miller v. State, 756 So.2d 1072, 1072 (Fla. 4th DCA 2000))
• The jury is likely to be confused or improperly influenced by evidence which applies to only one of several (two or more) defendants (McCray v. State, 416 So.2d 804, 806 (Fla. 1982))

Again, severance is entirely discretionary (e.g. up to the trial judge). However, in cases where the failure to sever co-defendants or charges was clearly erroneous (e.g. the trial judge abused their discretion), Florida District Courts of Appeal have REVERSED convictions and remanded the matter for a new trial. For more, click here.

Severance of charges is made significantly more likely (and a failure to sever may constitute an abuse of discretion) if either of the following are true (Fla. R. Crim. P. 3.152(a)(2)(a)):

• The consolidation of the charges (e.g. trying them in the same proceeding) seriously risks that evidence relating to each of the crimes will have the effect of “bolstering proof” of the other(s) (Crossley v. State, 596 So.2d 447, 450 (Fla. 1992))
• The prejudice to the defendant from a joint trial outweighs “judicial economy” (e.g. the efficiency of trying the counts together) (State v. Williams, 453 So.2d 824 (Fla. 1984))

Per Florida’s Rules of Criminal Procedure, two or more “related offenses” may be joined if these are based on the same act or transaction, or two or more related acts or transactions. But this does not mean they MUST be, and if prejudice is likely to result from joinder, severance of charges is warranted. Vinas v. State, 299 So.3d 456, 458 (Fla. 3rd DCA 2020)

Sometimes, a defendant will move for severance of co-defendants and the motion will be denied. A trial alongside a co-defendant carries inherent risks – especially if someone is charged as part of a conspiracy. This is because the co-defendant may choose to testify and incriminate the other defendant in the process.

Though potential harm to a nontestifying co-defendant’s defense does not require severance of co-defendants in Florida, there are certain situations that may arise at a joint trial (e.g. once the trial has actually commenced) in which ONE or BOTH (or all, if there are more than two) of the co-defendants ask for a mistrial.

A mistrial occurs when there is a legal error during the course of a criminal proceeding that is so significant, continuing the trial would result in a violation of the defendant’s due process rights and right to a fair trial (e.g. the error vitiates the proceedings).

If a mistrial is declared with a defendant’s consent (e.g. the defendant asks for it or stipulates to the State’s mistrial request), the State may try the defendant again. If a mistrial is declared over a defendant’s objection, retrial is BARRED by double jeopardy unless the mistrial was justified by “manifest necessity.” Merchant v. State, 201 So.3d 146 (Fla. 3d DCA 2006)

Sometimes, during a trial with two or more co-defendants (e.g. a joint trial), one defendant will choose to testify and the other(s) will not. If and when that occurs, there is a serious risk that the testifying co-defendant will say something that requires a mistrial. Smiley v. State, 295 So. 3d 156, 169 (Fla. 2020)

But when does a co-defendant’s testimony that implicates a nontestifying co-defendant require a mistrial to preserve the due process/fair trial rights of the nontestifying co-defendant? And when does a judge ABUSE THEIR DISCRETION by refusing to grant a mistrial at the nontestifying co-defendant’s request?

This seminal issue was recently addressed by one of Florida’s highest courts – the 6th District Court of Appeal. In that case, the defendant was accused of various offenses stemming from an attempted robbery. He was tried alongside the alleged co-conspirator.

When the co-conspirator testified, he disclosed that he and the nontestifying co-defendant sent texts to plan ANOTHER ROBBERY, separate from the one they were charged in connection to. The nontestifying co-defendant immediately moved for a mistrial, arguing that the testimony as to this “uncharged conduct” would contaminate the jury’s verdict (e.g. vitiate the proceedings).

The trial judge denied the motion, and both defendants were convicted on all counts. Appealing to the 6th DCA, the co-defendant who moved for a mistrial argued that the trial judge ABUSED his discretion by not granting the mistrial. He claimed that this error entitled him to a new trial.

Florida’s 6th DCA rejected this argument and AFFIRMED his convictions – but one judge did not agree. Let’s take a look at that case – Quesada v. State, — So.3d — (Fla. 6th DCA 2026) – and discuss what it means for defendants moving for severance (and mistrials) in Florida.

KEY CASE: Quesada v. State, — So.3d — (Fla. 6th DCA 2026)

In Quesada, the defendant (Quesada) was charged with  Conspiracy to Commit Robbery with a Firearm, Attempted Robbery, and Attempted Felony Murder. These arose from an alleged effort to commit a robbery alongside his co-defendant, who testified at trial.

At trial, the testifying co-defendant was cross-examined by the State, who asked him about a series of texts he allegedly exchanged with Quesada that were extracted from Quesada’s phone. The testifying co-defendant answered that the messages discussed “doing a robbery on someone else.” 

Quesada immediately moved for a mistrial, arguing that the co-defendant’s testimony as to this “uncharged conduct” would lead the jury to find him guilty on an improper basis (e.g. the belief that Quesada was predisposed to commit robberies), even if there was insufficient evidence of the charged crimes).

The judge DENIED Quesada’s mistrial motion after the State indicated that the co-defendant’s response was a “surprise” and vowing not to go “further down that road.” Moreover, there was no curative instruction given (e.g. to disregard the testimony and/or not consider it as evidence Quesada was guilty of the charged crimes). Quesada was convicted on all counts.

Appealing to the 6th DCA, Quesada argued that the trial judge abused his discretion by failing to grant a mistrial. However, the 6th DCA did not agree and AFFIRMED his convictions. The 6th DCA wrote:

“A mistrial is appropriate only where the error is so prejudicial as to vitiate the entire trial. A ruling on a motion for mistrial is within the trial court’s discretion.” Hamilton v. State, 703 So. 2d 1038, 1041 (Fla. 1997) (citation omitted). See, e.g., Smiley v. State, 295 So. 3d 156, 169 (Fla. 2020) (holding that co-perpetrator’s “vague reference to ‘when we normally operate like that’ [when questioned why he thought the defendant had gloves with him at the time of the murder] lacked any detail about other crimes and does not come close to meeting the high standard that justifies a mistrial”); Cole v. State, 701 So. 2d 845, 853 (Fla. 1997) (holding that witness’s statement that she “knew some history on” the defendant was “isolated and inadvertent and was not focused upon” and did not require a mistrial) … In the present case, Quesada’s co-defendant’s inadvertent, fleeting, and vague reference to a discussion about planning another robbery was not so prejudicial as to vitiate the entire trial … Accordingly, on this record, we cannot say the trial court abused its discretion by denying a mistrial.”

Put simply, because the 6th DCA did not believe that the testifying co-defendant’s answer was so prejudicial as to “vitiate the entire trial,” the trial judge did not reversibly err by failing to grant Quesada’s mistrial motion.

But one member of the court strongly disagreed. In a brief dissent, Judge Nardella of the 6th DCA wrote:

“Pedro Antonio Laureano Quesada was on trial for robbery-related offenses and felony murder with the central issue being whether he had knowledge that his co-defendant planned to rob the victim with a firearm. The State’s case against Quesada relied heavily on his co-defendant’s testimony—that he and Quesada changed their initial plan of selling the victim fake drugs for money to robbing him with a firearm. Against this backdrop, the co-defendant testified on direct examination, that he and Quesada discussed “[d]oing a robbery on somebody else.” This testimony of a separate, uncharged robbery, although not intentionally elicited by the prosecution nor mentioned at trial again, deprived Quesada of a fair trial by encouraging the jury to believe that Quesada was predisposed to commit robberies. On these facts, no curative instruction would have been sufficient to cure this prejudice, only a mistrial. …. I respectfully dissent.”

In essence, Judge Nardella concluded that the co-defendant’s testimony was a critical part of the State’s case against Quesada – and his discussion of the uncharged robbery entitled Quesada to a mistrial (as it unfairly prejudiced the jury against him). However, his opinion did not win the day.

In sum, Quesada v. State, — So.3d — (Fla. 6th DCA 2026) marks a significant development in Florida’s corpus of case law surrounding severance of co-defendants and mistrials. The 6th DCA majority held that:

• The testifying co-defendant’s brief mention of another robbery was not so prejudicial to Quesada as to “vitiate the proceedings”
• Because of this, the judge did not reversibly err (e.g. abuse his discretion) by denying Quesada’s request for a mistrial
• This required Quesada’s convictions to be AFFIRMED

Judge Nardella authored a brief dissent, in which he argued:

• The co-defendant’s testimony as to Quesada’s “uncharged conduct” was so prejudicial that it could not even be fixed via a curative instruction
• The co-defendant’s remark encouraged the jury to believe that Quesada was predisposed to commit the robbery 
• This encouraged the jury to render their verdict on an improper basis (e.g. uncharged conduct) – not based on the evidence presented as to the charges in the case
• As a result, the trial judge reversibly erred, requiring reversal of Quesada’s convictions

Florida’s criminal defense community should take note of Quesada v. State, — So.3d — (Fla. 6th DCA 2026), as it reveals how Florida’s District Courts of Appeal evaluate requests for a mistrial at joint trials.

If someone is arrested and formally charged in Florida and concerned about severance of charges or co-defendants, it is critical to find experienced and trusted legal representation as soon as possible. This decision could make the difference in whether or not someone faces a lengthy prison term and hefty fines.

Criminal Defense Attorney in Tallahassee, FL

Don Pumphrey, Jr. is a Former Prosecutor, Former State Police Officer, Lifetime Member of the Florida Association of Criminal Defense Lawyers; for over 25 years as a private defense attorney who is Trusted, Experienced, Aggressive in Criminal Defense as a Trial Attorney, Criminal Lawyer, Criminal Defense Lawyer for the accused in Florida State Courts located in Tallahassee, Florida but handling cases throughout the State of Florida.

Don Pumphrey, Jr. and the Tallahassee criminal defense lawyers at Pumphrey Law have decades of experience fighting criminal charges on behalf of clients and winning. Call Pumphrey Law now at (850) 681-7777 to learn more about what we can do for you. Our lawyers will be happy to provide you with a free consultation.

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