For the first time in court, Boston Marathon bomber Dzhokhar Tsarnaev dropped his blank, impassive demeanor and cried as his sobbing aunt briefly took the stand Monday in his federal death penalty trial before she was asked to step down to compose herself.

Tsarnaev, 21, wiped tears from his eyes quickly and fidgeted in his chair as his mother's sister sobbed uncontrollably. He had maintained a disinterested expression since his trial began in January.

The aunt, Patimat Suleimanova, cried as she sat down about 10 feet from Tsarnaev. The tears began falling before she began to testify, and she was only able to answer questions about her name, her year of birth and where she was born.

After a few minutes, Judge George O'Toole Jr. suggested that the defense call a different witness so she could compose herself. As she left the witness stand, Tsarnaev used a tissue to wipe his eyes and nose.

Five relatives -- three cousins and two aunts -- took the stand, though it was unclear if the aunt who broke down would be allowed to complete her testimony. As Tsarnaev was led out of the courtroom before the lunch recess, he blew a kiss at family members.

Tsarnaev was convicted last month of 30 federal charges in the bombings, including 17 that carry the possibility of the death penalty. He moved to the U.S. with his family in 2002 and committed the bombings when he was 19.

Prosecutors say Tsarnaev was an equal partner in the bombings with his radicalized older brother, Tamerlan, and have urged the jury to sentence him to death.

Tsarnaev's lawyers say Tamerlan, 26, was the mastermind of the attack and lured his brother into his plan. Tamerlan died days after the bombings following a shootout with police.

A cousin testified Monday that Dzhokhar was a kind and warm child, so gentle that he once cried while watching "The Lion King."

"I think that his kindness made everybody around him kind," Raisat Suleimanova said through a Russian translator.

Assistant U.S. Attorney William Weinreb pounced, asking her if she believes a deadly attack on innocent civilians can be considered kind. Tsarnaev's lawyer objected, and Suleimanova was not allowed to answer the question.

Shakhruzat Suleimanova, another sister of Dzhokhar's mother, Zubeidat, testified that Dzhokhar, Tamerlan and their two sisters were well-behaved as children.

"They were so good. They wouldn't hurt a fly. My sister's children were such good children," she said.

Suleimanova said the family was crushed when Zubeidat moved to the U.S. with her husband and children. Five or six years later, when Zubeidat returned to Russia for a visit, the family was shocked to see her sister --always a fashionable dresser -- covered in black clothing and wearing a jihab. Tsarnaev's lawyers have argued that Dzhokhar was influenced by his brother and his mother, who had become radicalized in the years before the bombings.

"We were all shocked. We were all in pain. We were very scared," she said. "We had never had people like that in our family. We prayed, we fasted, but no people like that."

Prosecutors urged the judge last week to press Tsarnaev's lawyers to make sure his relatives testify soon because 16 FBI agents have been assigned to guard and protect them while they are in the United States. The family members arrived in Boston on April 23.

"It's an enormous expense and distraction for the agency, and that's just part of the expense that the government has endured," Weinreb said during a sidebar discussion in court with Tsarnaev's lawyers and the judge, according to a transcript that was made public.