Graphic, emotional testimony continued Monday in the trial of admitted Boston Marathon bomber Dzhokhar Tsarnaev , who sat impassive as the survivors of the attack recounted scenes of bloody horror.

Jessica Kensky was the first witness to take the stand Monday as the trial entered its third day of testimony.

Kensky was with her husband, Patrick Downes, when the twin blasts rocked through Boylston Street on April 15, 2013, catapulting her “like a rocket.”

“There was smoke, there was blood. I was most focused on my husband, he was right next to me still, and his foot and his leg were kind of detached,” said Kensky . “A man came over as I was trying to fumble to put a tourniquet on Patrick and said, 'Ma'am you're on fire, you're on fire.'”

Tsarnaev is on trial for his life in the deadly attack that killed Martin Richard, 8; restaurant manager Krystle Campbell, 29, and graduate student Lingzi Lu, 23, and injured 264. He is also on trial for the fatal shooting of an MIT police officer three days later.

One of his defense attorneys last week admitted Tsarnaev and his late brother indeed carried out the attack, though the 21-year-old has pleaded not guilty to all charges.

Kensky lost her left leg on the day of the bombing. Doctors amputated her right leg this past January.

During her testimony, prosecutors showed the court surveillance images taken near the blast sites. Tsarnaev was seen walking with a backpack that prosecutors say held a homemade pressure cooker bomb. He is seen dropping it in a crowded area in front of Forum restaurant, making a phone call and walking away shortly before the blast.

Jurors also saw a graphic photo of bombing survivor Jeff Bauman consciously lying in a pool of blood, with the lower portion of his legs missing.

A friend of Lu's, fellow Chinese exchange student, Dan Ling Zhou, 24, held back tears as best she could while recounting her last moments with her friend. The pair was in front of Forum when the first blast rang out down the street. Zhou said she didn’t believe the blast was from a bomb, though Lu was panicked.

“[Lu] was scared. She was scared like everyone else around. I tried to calm her,” said Zhou, dabbing away tears.

Then the second bomb erupted nearby.

“I woke up and couldn’t hear anything. I saw blood all over the ground. There was a man in front of me… I can see his face is really scared and he’s yelling, but I cannot hear anything,” said Zhou. “He turned his face towards me, and I saw his legs were not there anymore.

Zhou took a series of slow, deep breaths on the stand before recalling her own wounds: “I was thinking it may be better if I lose my arms or legs because I think that I have a higher chance to survive because of my wounds — I had to hold things coming out from my inside,” she said.

Lu was still alive at that point, Zhou said. She was yelling for help. The friends were separated, and Zhou later learned of Lu’s death.

“Every time I wake up, I ask them whether or not they find her,” Zhou testified. “So I ask again. And she says, 'Oh,' she says, 'She passed away. You don’t know that?' So I guess everyone found out earlier. But they were trying to protect me, so they didn't tell me.”