Forensic witnesses described Watertown evidence recovery, vehicle damage, fingerprint findings, and blood testing. Jennifer Montgomery reported DNA matches to Sean Collier on glove samples and to Dzhokhar Tsarnaev on eight sweatshirt samples, with limits on mixed profiles and unsampled areas.
Full day summary
The court allowed defense voir dire on David Cahill's anticipated ballistics opinions but declined to postpone his testimony. It expressed a preliminary view that the opinions were likely admissible, subject to their foundation. The court also overruled the witness-list objection to Kelley King and directed the government to provide practical guidance linking witnesses to exhibits.
Robert McCarthy described recovering and opening two pipe devices at Moon Island to preserve evidence, clearing the Honda Civic, and removing a powder-filled container from the Mercedes. He interpreted a mark on the straight device's fuse as apparent attempted ignition and estimated two to three pounds of powder in the container, without an exact measurement. On cross-examination, he clarified that he saw smoke, not an explosion, and identified his approach street only after consulting a map.
Matthew Hess described retrieving a CD from the Mercedes and photographing the vehicle. The court admitted defense photographs over prosecution objections. Hess described apparent bullet damage to the windshield and headrests, while emphasizing that he was not a ballistician. Bruck argued that the damage supported an inference that the defendant had ducked while driving; that was counsel's proposed inference, not Hess's testimony about the defendant's actions.
Fingerprint examiner Patrick Moynihan identified prints belonging to Dzhokhar and Tamerlan Tsarnaev on vehicles and recovered items. On cross-examination, he agreed that fingerprints cannot be dated and that driving does not necessarily leave identifiable prints. He also confirmed receipts recovered from Tamerlan's wallet. D.J. Fife described handling property collected at the hospital and clarified that he witnessed, but did not personally perform, the clothing collection.
Stephanie Waite reported human blood on two separate gloves recovered from the Honda and on ten areas of the sweatshirt. She submitted samples for DNA and gunshot residue testing but gave no comparison or residue results. Jennifer Montgomery testified that a left-glove sample contained a mixture whose major male profile matched Sean Collier; the minor profile was insufficient for comparison. Another exterior glove sample yielded a single-source profile matching Collier. Eight tested sweatshirt samples matched Dzhokhar Tsarnaev alone, excluding Collier and Tamerlan. Montgomery limited those findings to the sampled areas and did not know whether every droplet had been swabbed.
FBI bomb technician Brian Corcoran described Watertown evidence collection and transfers. He said examination of the computer bag found modified electronics but no complete explosive device. He also identified a pressure cooker embedded in a separate parked Honda. His testimony stopped when the court adjourned.