Commonwealth v. Carleton (SJC-13509): Joint Venture Intent and Cell Phone Search Warrants in a Massachusetts Murder Case
When a homicide is committed from inside a moving vehicle, prosecutors often charge the driver as a joint venturer—arguing that driving was not neutral conduct, but intentional facilitation. In Commonwealth v. Michael A. Carleton (SJC-13509), the Supreme Judicial Court addressed two issues that come up repeatedly in serious firearm and murder prosecutions:
What evidence is enough to prove the driver shared the shooter’s intent to kill, and
How far police may go in seizing and searching a cell phone for photographs and metadata in a homicide investigation.
The Court affirmed the murder in the first degree conviction on a theory of deliberate premeditation, concluded the prosecutor’s opening and closing stayed within proper bounds, and rejected the defendant’s suppression arguments regarding the phone photographs and metadata. But the Court also vacated the firearm conviction—not because of the evidence, but because the jury were not instructed that the Commonwealth had the burden to prove the defendant lacked a valid license.
For defense lawyers, Carleton is a reminder that (a) “driver intent” cases are won and lost in details, especially vehicle positioning and timing, and (b) cell phone search fights often turn on “nexus” and the practical realities of forensic extraction—while still leaving room for aggressive litigation on the warrant’s scope.
The facts, as the jury could find them
The case arose from a Fourth of July shooting in Boston. The Commonwealth’s theory was stark: the defendant drove his girlfriend’s car while his front-seat passenger used a laser-guided firearm to shoot and kill a man seated on a sidewalk watching fireworks.
A central feature of the trial was video evidence—utility-pole cameras, MBTA bus video, and private cameras—capturing events before, during, and after the shooting. The Commonwealth also introduced:
Forensic evidence linking the driver to the car (fingerprints on the gear shift and driver-side door), and the passenger to the passenger-side area (fingerprints and DNA).
Clothing evidence recovered from the residence (a distinctive green “Airmax” shirt and shorts resembling what the driver wore on video).
Social media evidence suggesting a public Facebook account under “Michael ‘Mittyboi’ Carleton” posted a selfie showing the same shirt shortly before the shooting—and later became non-public.
Cell phone photographs and metadata extracted later pursuant to a separate warrant, including images showing the defendant wearing the “Airmax” shirt and location/time data.
The defense pressed two core themes: the Commonwealth failed to prove beyond a reasonable doubt that the defendant was the driver, and—most importantly—failed to prove he shared the shooter’s intent to kill.
Issue 1: When is a driver a joint venturer to murder?
The defendant’s argument was familiar: the passenger shot the victim; the driver “drove.” The defense relied on recent cases where appellate courts found insufficient evidence of shared lethal intent when the driver’s conduct looked more like presence, association, or post-crime assistance rather than a knowing and intentional facilitation of murder.
The SJC rejected that framing here, emphasizing what the jury could infer from the defendant’s manner of driving and conduct during the shooting itself—not merely after the fact.
What mattered to the SJC
According to the Court’s reasoning, the evidence supported a finding that the driver:
Returned to the same location after an initial pass, allowing an inference of reconnaissance and an intended target.
Pulled over to let traffic pass shortly before the second approach—allowing the jury to infer he was clearing the lane for the shooting.
Slowed/braked as shots were fired through the open passenger window—supporting an inference that he facilitated aiming and execution.
Would have seen the laser inside the car before the gun was fired, supporting an inference that he knew the passenger had a firearm and continued participating anyway.
Drove calmly and directly to a private lot one minute after the shooting, then walked away in a composed manner alongside the shooter, consistent with a planned escape rather than shock or surprise.
Had post-offense conduct (including social media changes) that could be argued as consciousness of guilt, which—while not enough alone—can reinforce other inferences.
The key distinction the Court drew was this: these were not facts of a driver who learns later what happened, or who simply gives someone a ride. This was a case where the jury could find the driver was present for the shooting in the car, maneuvered the vehicle to facilitate it, and continued the plan after learning a firearm was in play.
Defense takeaway
Carleton is a warning: when the Commonwealth can narrate a sequence of vehicle movements that look purposeful, it becomes easier for a jury to infer intent—even if there is no direct evidence of an explicit agreement. In these cases, the defense must force the jury to see alternative explanations as not just possible, but reasonable—traffic, road conditions, confusion, panic, or non-culpable decision-making that is consistent with innocence.
Issue 2: Prosecutorial argument—where the line is (and isn’t)
The defendant challenged the prosecutor’s opening and closing as improper, claiming misstatements, burden shifting, personal belief, and personal assurances.
The SJC held the prosecutor stayed within permissible bounds. Two practical points are worth highlighting:
Prosecutors are allowed to argue intent by inference—particularly where direct evidence of state of mind is rarely available. So long as the argument is anchored in trial evidence and reasonable inferences, the Court will not treat it as “facts not in evidence.”
General statements about the strength of the Commonwealth’s evidence are often treated as permissible “appraisal,” not impermissible vouching—especially when framed as argument based on what the jury can see in the exhibits (like surveillance video).
Issue 3: The cell phone—nexus, delay, and scope
This part of the decision is especially important for modern homicide and firearms cases, where police routinely seek phone data and images to place a person, confirm clothing, build timelines, and corroborate identity.
(A) Was there probable cause (a “nexus”) to seize the phone?
The defense argued there was no sufficient nexus between the phone and the crimes to justify the warrantless seizure.
The Court concluded there was enough particularized reason to believe the phone would contain relevant evidence—especially the selfie in the distinctive shirt posted shortly before the shooting, the reasonable inference that selfies are taken on phones, and the phone’s proximity to where the defendant was sleeping.
Defense practice point: “Nexus” fights are winnable, but they require disciplined framing. The question isn’t whether phones often have evidence—it’s whether police had a particularized reason to believe this phone likely had specific evidence tied to the alleged crime.
(B) Was the search “unreasonably delayed”?
The Court addressed the fact that forensic unlocking and extraction can take a long time, particularly when specialized tools are used to bypass passcodes. The SJC was not persuaded that the timeline was unreasonable under the stipulated facts, particularly where police connected the phone promptly to the unlocking process and there was no showing that the process could have been faster.
Defense practice point: If you are going to litigate delay, you need a record that distinguishes (1) unavoidable technical time from (2) investigative inertia. That may require discovery and testimony about queueing, prioritization, tool availability, and why the device sat untouched (if it did).
(C) Did the search exceed the warrant’s scope?
The defense also argued the search exceeded the scope of the warrant, which was targeted to photographs of the defendant in the “Airmax” shirt around the relevant date.
The Court rejected the claim on the record described, noting that most images admitted were squarely within the described category, and the remaining image did not show the police rummaged beyond what was reasonably necessary to locate the authorized evidence.
Defense practice point: Scope arguments often rise or fall on the search methodology. If the record is “silent” about how the search was executed, appellate courts tend to defer. A strong suppression strategy aims to create a factual record about how officers navigated files, what filters they used (or didn’t), and whether they used the warrant as permission to perform a broad exploratory search.
The surprise ending: the firearm conviction gets vacated
Even though the defendant didn’t raise the issue, the SJC vacated the unlawful possession of a firearm conviction and remanded for further proceedings because the jury were not instructed that the Commonwealth bore the burden to prove the defendant did not have a valid license—an issue shaped by the post-Guardado landscape.
This portion of Carleton matters beyond homicide cases. It’s a reminder that firearm prosecutions can fail not because of the facts, but because of burden and instruction errors that go to the elements the Commonwealth must prove.
What Carleton means if you or a loved one is facing a homicide or firearms case in Massachusetts
Carleton reflects two realities of modern prosecution:
The Commonwealth will use video, location data, and digital timelines to turn circumstantial evidence into a narrative of intent.
Courts will often allow juries to infer intent from driving behavior and coordinated movement, especially when the shooting occurs in the driver’s presence and from within the car.
At the same time, the decision shows there are still pressure points:
Joint venture intent is not automatic; it must be proved beyond a reasonable doubt.
Nexus and scope challenges to phone searches remain real—particularly when the defense makes a record.
Firearm convictions remain vulnerable where the jury aren’t properly instructed on the Commonwealth’s burden.
If you are under investigation, charged, or indicted in a homicide or firearm case, early, strategic lawyering matters: evidence preservation, motion practice, and building the record can change the outcome.
Q&A: Commonwealth v. Carleton (SJC-13509)
1) Can a driver be convicted of murder if the passenger pulled the trigger?
Yes. Under joint venture principles, the Commonwealth can convict a driver if it proves the driver knowingly participated and shared the shooter’s intent. Carleton emphasizes that intent can be inferred from coordinated actions before, during, and after the shooting—especially how the driver positions and maneuvers the vehicle.
2) What makes “shared intent” easier for prosecutors to prove in a driver/passenger shooting?
Evidence that the driver did more than simply drive—such as circling the area, clearing traffic, slowing at the moment of the shooting, remaining present while shots are fired from inside the car, and executing an orderly escape.
3) Can police seize a phone without a warrant during a homicide investigation?
Sometimes—but they still need probable cause to believe the phone contains particularized evidence, not just the general idea that “phones have evidence.” In Carleton, the Court found a sufficient nexus based on the selfie and other circumstances tying the phone to that evidence.
4) Does it matter if it takes months to unlock a phone?
It can, but it depends on whether the delay is reasonable in context. Carleton suggests that lengthy unlocking/extraction timelines may be upheld where police start the process promptly and the duration is driven by technical limitations rather than investigative neglect.
5) What happened to the firearm conviction in Carleton?
It was vacated because the jury were not instructed that the Commonwealth bore the burden to prove the defendant did not have a valid license—an instructional error that remains important in Massachusetts firearm cases.
Call us if you need defense counsel
If you or a loved one is facing a homicide allegation, firearms charge, or a serious search-and-seizure issue in Massachusetts, you need experienced counsel early—before the Commonwealth’s narrative hardens into “fact.” Call Benzaken, Sheehan & Wood, LLP at (508) 897-0001 to schedule a consultation.