Gunshot studies, phone records covered in Hernandez trial Thu.

Jury selection begins in the double murder trial of former New England Patriots tight end Aaron Hernandez Tuesday, Feb. 14, 2017, in in Suffolk Superior Court in Boston. (Pat Greenhouse/Boston Globe via AP, Pool)

Continuing Coverage of the Aaron Hernandez Double Murder Trial »

BOSTON (WPRI) — A jury had to get crash courses Thursday on particles and residue created when a gun is fired, as well as records made for cell phone calls and text messages, in the double murder trial of former New England Patriots tight end Aaron Hernandez.

Hernandez is charged with killing Daniel de Abreu and Safiro Furtado in June 2012, after prosecutors say he felt disrespected when one of the men bumped into him at a nightclub in Boston’s South End and spilled his drink.

Journalists for WBZ-TV, WFXT-TV, WHDH-TV and WCVB-TV, among others, have been posting minute-by-minute happenings on Twitter from courtroom seats.

After a crime lab analyst said on cross-examination that no DNA showed up on a key fob from the vehicle Hernandez was allegedly riding in at the time of the killings, Massachusetts State Police Crime Lab forensic scientist John Biello was called to the stand to discuss gunshot residue. Two items he tested from the Toyota 4Runner had no gunshot residue on them, and the vehicle itself tested negative as well.

A Boston Police criminologist and DNA expert, Julie James, testified that there wasn’t sufficient evidence on the alleged murder weapon to conclude that Hernandez handled the gun.

The mother of Jailene Diaz-Ramos was also called to the stand to be questioned about her daughter’s car, where the weapon was found after a 2013 crash.

Later, phone records showed Hernandez called his fiancee, Shayanna Jenkins, about the time of the murders, 2:37 a.m., for a 13-second phone call. An expert from AT&T’s wireless division said Hernandez’s phone placed the call while in transit near 790 Boylston Street. The morning after the killings, people tried to text Hernandez, but his cell phone was not operational; it either was shut off, the battery had died, or it had been placed in “airplane mode.”