Boston Marathon bombing trial: 7 things to know

The trial of Boston Marathon bombing suspect Dzhokhar Tsarnaev continues Monday, with the defense likely to begin presenting its case. Here are seven things to know about the trial so far:

• Tsarnaev's attorneys have all but conceded the most serious charges. In her opening statement, lead attorney Judy Clarke said Tsarnaev was involved in carrying out the April 15, 2013, attack that left three people dead and more than 260 injured. "It was him," Clarke told the jury. But the defense contends that he was under the influence of his older brother, Tamerlan.

• Jurors have taken in graphic testimony and photos of injuries and deaths, including testimony from the father of an 8-year-old boy who described the moment when he looked down at his son's pale, torn body and realized he wouldn't make it. They also heard from Jessica Kensky, a nurse who had two legs amputated. She recalled that she and her husband, Patrick, who also lost a leg, were knocked off their feet by the first explosion. "These are war wounds," she said.

• FBI explosives expert Edward Knapp testified that each of the two pressure cookers near the marathon finish line could contain as much as 16 pounds of explosive material. They were rigged similarly to those detonated in overseas attacks, he said. "A suicide bomber would have this type of configuration." Jurors even held a pressure cooker mock-up of the bombs, their eyes widening at the heft of the device that was filled with electronics, batteries, BBs and nails.

• Jurors saw video of Dzhokhar Tsarnaev entering a Whole Foods Market in Cambridge, Mass., 23 minutes after the bombs went off. In the video, he picks out and pays for a half-gallon of milk, then runs back into the store to exchange it for a different one. Prosecutors said the actions show that Tsarnaev had a clean conscience. The jury also saw surveillance video from the University of Massachusetts-Dartmouth fitness center showing Tsarnaev working out a day after the bombings.

• Jurors learned that two hours after the bombs went off, Tsarnaev tweeted: "Ain't no love in the heart of the city, stay safe people." The next day, at 10:43 p.m., Tsarnaev told his followers: "I'm a stress free kind of guy."

• Police told jurors that four days after the bombings, officers engaged the brothers in a harrowing, eight-minute shootout, punctuated by a massive explosion from a pressure-cooker bomb that rattled the suburban neighborhood. "It was non-stop," recalled Watertown, Mass., police officer Joseph Reynolds. The shooting ended when he and other officers managed to tackle Tamerlan, but Dzhokhar, driving a stolen SUV, struck and killed his brother. The younger brother fled the scene, but hours later police arrested him, wounded and bleeding, in a boat stored in a nearby backyard.

• During a visit to a flatbed tow truck, jurors examined the bullet-riddled, bloodstained boat, named Slipaway II. It had at least 108 bullet holes in it, as well as faded bloodstains. Jurors saw some details that hadn't been evident before, including writing carved into a wooden fixture on the fiberglass boat. It said, "Stop killing our innocent civilians."

Tsarnaev, 21, is charged in a 30-count indictment, including 17 counts that could carry the death penalty.

Contributing: Jeffrey MacDonald in Boston