BOSTON >> The prosecution rested its case Thursday during the penalty phase of Boston Marathon bomber Dzhokhar Tsarnaev’s trial after playing a video showing the mother of 8-year-old Martin Richard crouched over him and resting her head on his chest as he lay dying.

“I heard ‘please’ and ‘Martin’ being uttered by Denise Richard,” said Steve Woolfenden, a man who was lying on the pavement next to Martin and his mother after the second bomb exploded.

“Just pleading with her son,” Woolfenden said, as prosecutors played a video that showed Denise Richard leaning over close to her son, then putting her head down on him.

The boy bled to death on the sidewalk.

Woolfenden’s left leg had been sheared off. He described frantically trying to get his 3-year-old son, Leo, out of his stroller. As he lay on the pavement, he saw Martin and Denise Richard.

Prosecutors, who rested their case Thursday, will get a chance for rebuttal after the defense presents its case, which is expected to begin Monday.

Tsarnaev was convicted this month of all 30 charges against him. Three people were killed and more than 260 others were wounded when twin bombs exploded near the finish line of the marathon April 15, 2013.

A jury must decide whether to sentence him to life in prison or to death.

Also testifying Thursday was Heather Abbott, whose left leg was amputated after the bombing. She described her own painful loss, then identified photos of 16 others who lost limbs as prosecutors tried to drive home the brutality of the attack to jurors who will decide the bomber’s fate.

Abbott, of Newport, Rhode Island, said she was catapulted through the entrance of a restaurant when the second bomb exploded. She said her foot felt like it was on fire, so she began crawling to follow a crowd of people trying to get away from the bomb.

Later, in the hospital, a doctor recommended amputating her left leg below the knee. Her heel had been entirely blown off, and her foot was severely damaged.

“It was probably the hardest decision I’ve ever had to make,” she said.

Prosecutor Nadine Pellegrini asked Abbott to identify photographs of other amputees she has come to know since the bombing. The photos showed the amputees wearing prosthetic limbs, in wheelchairs and on crutches.

Another amputee, Marc Fucarile, testified Thursday from a wheelchair.

Fucarile, whose right leg was blown off in the bombing, glared at Tsarnaev as he sat about 10 feet away at a table with his lawyers. Tsarnaev did not look at him and stared straight ahead impassively.

Fucarile said he has had more than 60 surgeries. Two years after the bombing, it is still unclear whether his left leg can be saved, he said.

“We are going to try,” he said.