Jason Costello

Jason Costello testified for the prosecution on Day 30 about surveying the Boston Marathon bombing scenes and checking evidence-location graphics against field measurements. The FBI special agent and Evidence Response Team member explained how total-station equipment measures angles, distances, and elevations to produce electronic scene drawings.

Costello estimated that he spent six or seven days documenting Scene B near the Forum restaurant, mapping approximately 407 items of physical evidence and human remains and taking about 4,000 measurements, including fixed scene features. Search teams located items and called them to his attention for measurement from established control points. Elevated recovery locations required measurements from a rooftop. He described comparing laboratory graphics with his field drawings, while noting that he was not familiar with current use of the CAD program.

At Nadine Pellegrini's request, the court permitted Exhibit 620 to be displayed as a chalk, not admitted into evidence. Judy Clarke agreed to that use while expressing concern about admission. Costello acknowledged that he had not labeled the items, did not know who labeled each one, and understood that the graphic omitted some mapped items. His description of evidence concentrations at both bombing scenes concerned recovery locations, not who placed the devices. The defense asked no questions.