Updated on February 3rd, 2021 at 10:49 pm

Creating Juror Doubts About Lab Testing During Cross-Examination

As part of your Milwaukee DUI law trial, you and your attorney will have a chance to cross-examine each of the witnesses questioned by the prosecutor in your case. After the prosecutor finishes questioning the lab scientist who analyzed your blood sample, your defense lawyer will perform cross-examination. The goal of this cross-examination is to cast doubt on the lab analyst’s testimony by showing the automated process of blood testing for DUI prosecutions.

Contrary to what the jury may believe initially, a lab scientist does not use a microscope to personally look at each prospective defendant’s blood sample. In reality, a lab machine performs the analysis through an automated process. Your Milwaukee DUI lawyer will try to show the jury that the actual procedures used by the lab analyst required little oversight by the analyst who tested your blood sample.

Cross-examination of the prosecutor’s lab analyst may start with your defense lawyer asking the scientist whether he personally tested your blood sample using lab equipment. If the scientist answers that he did analyze your blood sample on a lab machine, your lawyer may ask how many samples were included in the same batch on the machine at one time. If the lab analyst answers that question evasively, your lawyer may need to ask for a specific number of samples included in the same batch; your lawyer will want to show that the lab analyst handled many samples in one batch at the same time.

As the cross-examination continues, your defense lawyer may also ask the lab analyst whether he left the room while a machine continued to process the batch containing your blood sample. The goal is to show that the scientist may not have personally watched the machine as it automatically processed the results now offered by the prosecution as evidence in your DUI case.

If you need assistance with your strategy for cross-examination, whether related to the automated processing of your blood sample or another aspect of your case, Vanden Heuvel & Dineen, Milwaukee DUI lawyers, may be able to help. Top Rated Wisconsin DUI Defense Attorney Nathan J. Dineen is available 24/7 to answer your questions. He is a certified Field Sobriety Test Instructor and is highly trained in the Wisconsin Breath test machine and blood records. Free Consultation. Call 1-877-384-6800.