New Jersey criminal defense

Courts-Ruling-on-Diminished-Capacity-300x300 The New Jersey Supreme Court has answered a question that has lingered in our criminal courts for decades: can a defendant obtain a diminished capacity jury instruction on lay testimony alone? In State v. Mustafa, a unanimous decision issued on August 3, 2026, the Court held that expert testimony is required both for a defendant to invoke the diminished capacity defense and for a trial court to instruct the jury on it. The Court affirmed the Appellate Division and confirmed that an expert is necessary to support an insanity defense. For anyone who handles serious violent crime cases, this opinion changes how mental health evidence must be developed, and it changes it well before trial begins.

The case arose from a late night shooting on a Monmouth County highway in May 2018. The defendant was driving with his then girlfriend when the victim, traveling on the same roadway, turned on her high beams because one of her headlights was out. The defendant became upset, pulled over to let her pass, then accelerated until he nearly struck her bumper while flashing his own high beams. As her car began to exit, he put his vehicle in neutral, rolled down his window, drew a handgun, and fired. She died of a gunshot wound to the head. A grand jury returned a six count indictment charging first degree murder, weapons offenses, and endangering. Defense counsel initially served notice of an insanity defense, but the defendant later instructed his attorney to withdraw it, and a pretrial memorandum recorded that decision in plain terms, noting that the insanity defense was withdrawn and that there would be no psychiatric expert testimony. The trial court found the waiver knowing and voluntary.

Diminished capacity, however, was raised explicitly at trial, and a fair amount of lay evidence about the defendant’s mental health reached the jury. His then girlfriend testified that he had begun seeing her psychiatrist to obtain Adderall because he liked how it made him feel, that he smoked marijuana daily, and that he had immersed himself in conspiracy research. She described his belief that he was the target of gang stalking, that people were shooting laser beams, radiation, and concentrated microwaves at him, and that he wore tin foil under a baseball cap and helmet to deflect the rays. She said his statements reminded her of a relative who has schizophrenia. On the night of the shooting, she testified, he took Adderall three times within several hours, yelled about people trying to hit him with radiation and follow him, and screamed that he could not take it anymore and had to fight back. The defendant did not testify and called no witnesses. When counsel requested a diminished capacity charge at the close of evidence, arguing that a medical diagnosis was not required, the trial court denied it because there was no medical or expert testimony in the record. The jury convicted on all counts and the defendant received an aggregate life sentence.

Judicial-papers-and-evidence-folder-300x300 Prosecutors are given considerable room to be forceful at trial. They can strike hard blows, paint vivid pictures for the jury, and provide context for how an investigation unfolded. But there is a line between vigorous advocacy and conduct that undermines a defendant’s right to have guilt or innocence decided solely on the evidence. In a unanimous opinion issued on February 25, 2026, the New Jersey Supreme Court drew that line in State v. Gerald W. Butler, reversing a drug conviction and ordering a new trial after finding that no single trial error required reversal, but the accumulation of errors together did.

The case grew out of “Operation That’s All Folks,” a multi-agency investigation launched b y the Cumberland County Prosecutor’s Office Organized Crime Bureau in response to a series of shootings in Millville. Butler was not connected to those shootings. He became a subject of the investigation only after wiretap surveillance captured a call in which participants discussed a firearm purchase and police identified his voice. From there, investigators obtained a wiretap on Butler’s phone, surveilled an apartment he was seen entering, and ultimately executed a search warrant that turned up heroin, cocaine, drug paraphernalia, and two revolvers. Butler was acquitted of all weapons charges but convicted of CDS offenses, including distribution and conspiracy.

The problems at trial were multiple. First, the prosecutor opened by comparing the case to The Wire, the HBO drama famous for its portrayal of organized crime, murder, and urban violence in Baltimore. Defense counsel objected immediately. The trial court overruled the objection, reasoning the comments were not overly prejudicial. The Supreme Court disagreed that the analogy was appropriate, noting it invited jurors to associate Butler with violent criminal conduct untethered to anything the evidence would actually show. Still, because the reference was isolated and not repeated in closing, the Court declined to call it reversible error standing alone. Second, throughout trial, law enforcement witnesses testified extensively about gun violence, weapons trafficking, and organized criminal activity in Millville, all of it unconnected to Butler personally. The Court found this testimony improper, noting that while police can explain how an investigation started, background context cannot be used as a backdoor way of suggesting a defendant’s propensity for crime. Again, though, the Court stopped short of reversal on this ground alone, pointing to the substantial evidence on the drug charges and the jury instructions limiting consideration to the charged offenses. Third, despite a pretrial agreement between the parties and a court directive to use only the phrase “lawful search,” the State repeatedly elicited testimony that Butler was the “target” of a search warrant, triggering exactly the kind of improper inference the Court had cautioned against in State v. Cain, that a judge’s authorization of a warrant amounts to pre-approval of guilt. Once more, because the jury acquitted Butler on the weapons counts, the Court found this error alone would likely satisfy the harmless error standard.

Articles Tagged with New Jersey criminal defense

New Jersey Supreme Court Holds That Diminished Capacity Requires Expert Testimony

When Small Errors Add Up: Drug Conviction Overturned in State v. Butler