By Patrick Aguilar, Camellia Dehdashti, Janelle Gonzalez, Estefany Romero
SAN FRANCISCO — During a jury trial Tuesday in San Francisco Superior Court, a testifying officer admitted to failing to follow protocol outlined in the police manual during a DUI arrest.
On July 22, 2024, the accused was involved in a traffic collision while searching for parking. A SFPD officer testified that she and her partner received a call about the incident at 3:14 a.m. and arrived at the scene around 3:19 a.m.
When they arrived, one officer spoke with the accused while the other spoke to the complaining witness. The officer testified she talked to the witness and explained the citizen’s arrest form, which the witness could sign to affirm that she saw the accused behind the wheel, allowing the officer to arrest him.
The officer claimed she presumed the accused was under the influence due to his slurred speech, unsteady movements, and incoherent statements. Deputy Public Defender Stack showed an eight-second body cam video in which the accused appeared calm and composed as he walked toward the officer.
The officer stated she asked the accused to take a field sobriety test, which he declined, exercising his constitutional right. Within 25 seconds of that interaction, he was taken into custody.
DPD Stack asked the officer if she had informed the accused of his right to decline field sobriety tests, as required by the SFPD manual. She admitted she had not. Stack also asked whether she had conducted a thorough search and questioned all involved parties, per department policy. She again responded no.
As part of the investigation, the officer testified she conducted a limited search of the accused’s vehicle, though that information was not included in her report. A full search was not conducted due to collision damage on the passenger doors.
Deputy District Attorney Watson presented photos of a duffel bag in the back seat and an unknown item in the front. The officer said no alcohol was found in the car and acknowledged she did not search the duffel bag or the front seat compartment.
Watson then called Dr. Jessica Winborn, a forensic toxicologist from the Office of the Chief Medical Examiner, to testify as an expert in drug and alcohol testing. Dr. Winborn explained the cognitive and psychomotor effects of alcohol and described how blood alcohol content is calculated using field tests or blood draws.
In this case, the accused’s blood was drawn at 5:20 a.m., roughly two hours after the incident. Dr. Winborn reviewed the analysis and found the BAC at that time to be 0.162 percent. When asked to estimate the BAC at 3:19 a.m., she said it could have been approximately 0.192 percent, based on the accused’s height, weight, and age.
During cross-examination, Stack questioned the assumptions behind that estimate. Dr. Winborn said she used available information and had to rely on approximations given the lack of specifics.
She ultimately admitted there were multiple possibilities for the accused’s BAC at the time of the incident, and that it could have been 0.192 percent, lower, or higher. She noted that more information would have been necessary to eliminate the margin of error.
The jury is scheduled to hear Stack’s closing argument on Monday.
