Elena Graff

Elena Graff testified for the defense on Day 42 about latent-print comparisons involving Dzhokhar and Tamerlan Tsarnaev. An FBI laboratory examiner at Quantico, she led the specialized examination team and believed more than 800 items had been examined. Her comparisons addressed the defense's distinction between the brothers' roles, but identified sources of impressions rather than assigning responsibility for planning or construction.

On direct examination, Graff identified two Dzhokhar fingerprints and six Tamerlan fingerprints on a Tupperware container. She reported Tamerlan matches on a transmitter, pressure cooker lid, tools, tape, documents, and notebooks, while several tested items yielded no matches to Dzhokhar. She believed notebook processing covered the covers and the first five and last five pages. More than 500 Boylston Street items yielded six latent impressions; prints on cardboard and paper from a destroyed backpack were identified to Tamerlan, with no matches to Dzhokhar from Scene A or Scene B. The court permitted her to describe examined tools but limited testimony about where they were recovered.

On cross-examination, Graff explained that explosions, wiping, evaporation, gloves, and insufficient residue can prevent recovery. Missing prints did not establish that someone had never touched an item. She agreed that ordinary handling could explain household prints and corrected counsel's descriptions of several items and impressions. She also confirmed both brothers' fingerprints on the bomb found in the Mercedes abandoned on Laurel Street in Watertown.

Redirect returned to the preservation of prints on cardboard and paper, which absorb finger sweat. Graff agreed that encasing cardboard reduces accidental loss and confirmed developing Tamerlan's fingerprints from cardboard collected on Boylston Street after the blast. The court allowed questions but barred a proposed demonstration with held-up cardboard. On recross, she agreed that the impressions could have remained for months or years: she could establish that someone touched an item, but not when.