Walker v. State
| Decision Date | 09 December 2020 |
| Docket Number | No. 4D19-3289,4D19-3289 |
| Parties | Samuel M. WALKER, Appellant, v. STATE of Florida, Appellee. |
| Court | Florida District Court of Appeals |
Antony P. Ryan, Regional Counsel, and Louis G. Carres, Assistant Regional Conflict Counsel, Office of Criminal Conflict Regional Counsel, West Palm Beach, for appellant.
Ashley Moody, Attorney General, Tallahassee, and Melynda L. Melear, Senior Assistant Attorney General, West Palm Beach, for appellee.
In this trial, a detective testified to the area of cell site coverage which placed appellant's cell phone in the area of the crime during the time of its commission. Over objection, the trial court found that the detective's testimony satisfied the standards of Daubert and permitted the detective's testimony. We find that the trial court did not err and that the detective satisfied the rigors of Daubert . The trial court found that the detective could testify as to the cell site mapping in this case even without having knowledge of the underlying algorithms, or how the system works in every technical detail, to generate the output of information. We thus affirm appellant's conviction for first-degree murder195 with a firearm while wearing a mask and six counts of robbery with a firearm while wearing a mask.
On January 4, 2013, six individuals, including the owner and her boyfriend, were in a restaurant that had recently closed for the evening. When the boyfriend went to let one of the individuals out the back door, two men rushed into the restaurant with their guns pointed. The robbers yelled at everyone to get down and took the victims’ property, including the owner's Chopard watch. The robbers fired shots, killing the boyfriend.
A few hours after the robbery, the two codefendants and a third man, later identified as appellant, entered a convenience store and sold the Chopard watch to a man who buys jewelry for cash. The man who purchased the watch later contacted the police and provided them with the codefendants’ names and phone numbers. During an investigation, the police learned that appellant was an acquaintance of the codefendants.
The police recovered a 9mm bullet and casing at the crime scene as well as a 9mm pistol from a codefendant's residence. DNA from the 9mm pistol and the Chopard watch matched appellant's DNA.
Phone records from appellant's and the codefendants’ phones were admitted into evidence without objection. The records showed the dates and times of phone calls as well as the cell phone tower ID number for those calls. During voir dire, a detective testified that he used a cell phone mapping and analytical program, TRAX, to diagram the estimated location of the mobile devices. The detective explained there is no such thing as a standard or average range for a cell tower; instead, there are gradual diminishing signal strengths. Once a device travels outside the beam with the coverage area, there is an estimated coverage or estimated handoff area represented by a horizontal plane. The program creates an illustration using data from the phone records.
The detective stated that cell phone towers use directional antennas that are affixed to the cell site or cell tower. The detective had participated in drive testing or field scans to test the program's accuracy. During such testing, they take radio frequency measurement equipment out into the field and conduct network scans that capture the signal strength and quality of the cell site. The detective had done this two or three months prior to trial. The detective testified that "it's extremely accurate." He did not know the error rate because "you have to have an understanding of how the technology works."
The detective explained that the program creates an illustration based off an algorithm "using field scans or radio frequency coverage and other field tests that are used to provide a cellular network pattern based off handoffs, subscriber density, tower density, network capacity, elevation and terrain." The detective did not know the algorithm.
The defense moved to exclude the detective's testimony because it was unknown how the TRAX system works and there was no known rate of error. The trial court treated the motion as a Daubert challenge and ruled to admit the testimony.
The detective then testified that he had over 100 hours of training in cell phone mapping and analytics and had been involved in over 200 cases involving cell phone mapping and analytics. He had testified in more than ten cases in Palm Beach County.
The detective testified that cell phone companies provide law enforcement the location of cell phone towers and the direction from the tower of the antenna being used to facilitate the transmission. The detective received cell phone records from three different cell phones belonging to appellant and the codefendants to conduct mapping. The detective concluded that appellant's and the codefendants’ cell phones placed them in the area of the restaurant during the timeframe of the crime and in the area of the convenience store during the timeframe the watch was sold. The detective emphasized that cell site information does not give an exact location but rather an approximate geographical area or region. On cross-examination, the detective testified that he has been using TRAX since 2016 and that before TRAX, he would do the mapping manually.
In a statement to police, appellant confirmed his phone number, stated he knew the codefendants, admitted he had his phone with him on the night of January 4, and identified himself in the convenience store surveillance video.
The jury found appellant guilty as charged.
Appellant argues that the trial court erred in admitting the detective's testimony regarding the cell site tower coverage because the detective's testimony did not meet the standard for admissibility under Daubert . Appellant claims that the detective lacked sufficient knowledge to testify about the computer-generated map which connected appellant's cell phone to cell towers near the scene of the crime during the period of time when the crime was committed.
The state argues that the detective had sufficient familiarity and understanding of cell phone analysis and mapping to be able to testify to the output of the computer-generated cell site map. We agree.
We consider a trial court's ruling on the admissibility of expert testimony under section 90.702, Florida Statutes (2019), under the abuse of discretion standard of review. Kemp v. State , 280 So. 3d 81, 88 (Fla. 4th DCA 2019).
Section 90.702, Florida Statutes, codifies the Daubert standard as follows:
A trial judge has the role of gatekeeper under Daubert . The judge is to "ensure that any and all scientific testimony or evidence admitted is not only relevant, but reliable." Daubert , 509 U.S. at 589, 113 S.Ct. 2786. As a gatekeeper, the trial judge must make "a preliminary assessment of whether the reasoning or methodology ... properly can be applied to the facts in issue." Id. at 592-93, 113 S.Ct. 2786. Daubert lists relevant factors for the trial court to consider when determining the reliability of expert testimony, such as whether the theory or technique can be and has been tested, whether the theory or technique has been subjected to peer review and publication, the known or potential rate of error and the existence and maintenance of standards controlling the technique's operation, and general acceptance in the scientific community. Id. at 593-94, 113 S.Ct. 2786. The Daubert list of "factors neither necessarily nor exclusively applies to all experts or in every case."
Kumho Tire Co. v. Carmichael , 526 U.S. 137, 141, 119 S.Ct. 1167, 143 L.Ed.2d 238 (1999). The Daubert test of reliability is flexible. Id. " Daubert makes clear that the factors it mentions do not constitute a ‘definitive checklist or test.’ " Id. at 150, 119 S.Ct. 1167 (citation and emphasis omitted). The trial judge has "broad latitude" in evaluating expert testimony. Id. at 153, 119 S.Ct. 1167.
In admitting the detective's testimony, the trial court initially relied on Gordon v. State , 863 So. 2d 1215 (Fla. 2003), and Perez v. State , 980 So. 2d 1126 (Fla. 3d DCA 2008). In Gordon , the defendant argued the trial court erred in denying an evidentiary hearing on his claim that trial counsel was ineffective for failing to object to expert opinion testimony of two witnesses. 863 So. 2d at 1219. The supreme court found that the testimonies of the witnesses did not constitute expert testimony. Id. One witness factually explained the contents of phone records that linked the defendant to the murder, and the second witness, a detective, factually compared the locations on the phone records to locations on the cell site maps. Id.
In Perez , the Third District found that testimony of records custodians from cell phone companies did not constitute expert testimony under section 90.702 and therefore was properly admitted. 980 So. 2d at 1131. "As in Gordon , the custodians factually compared the locations on the phone records to locations on the cell site maps." Id. The court explained:
[The witness] testified that a typical...
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