The brothers rented a Glock 34 and Glock 17 - both guns that fire 9 mm ammunition, Riportelli told the court.
The Tsarnaevs allegedly used a Ruger 9mm to kill MIT police officer Sean Collier three days after the marathon blasts and, hours after that, to fire at police during a violent firefight. Tamerlan was killed in that gun battle, while Dzhokhar managed to escape and hide for a few hours before being apprehended.
In surveillance video from outside the gun shop, Dzhokhar Tsarnaev appears to be wearing the same colorful Adidas sweatshirt he wore on April 18 in the hours after he and his brother purportedly shot Collier. Photos that show Tsarnaev's capture from his hideout on a dry-docked boat show him wearing a similar article of clothing, which is now marked as evidence in the case.
There was also testimony today from Massachusetts State Police crime scene technicians about the Ruger P95 and fingerprints lifted from a pellet gun recovered in Watertown behind Tsarnaev's green Honda. DzhokharTsarnaev's prints were on the pellet gun, and one of Tamerlan's prints was found on the Ruger, a trooper testified.
Dzhokhar Tsarnaev faces a possible death penalty if convicted on some 30 counts related to the Boston Marathon bombing. Though his defense admitted in opening statements he was involved in the blasts, he has pleaded not guilty and his attorneys have attempted to portray Tamerlan as the mastermind and leader of the deadly attack who exerted his influence over his younger brother.