Computer expert: Tsarnaev's brother searched for bomb parts

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Boston Bombing Prosecution Rests Its Case


BOSTON (AP) - A computer expert testifying in the Boston Marathon bombing trial says Dzhokhar Tsarnaev's older brother did Internet searches on bombing components in the weeks before the 2013 terror attack.

The expert says search terms on Tamerlan Tsarnaev's laptop included "detonator, "transmitter and receiver" and "fireworks firing system." He says Dzhokhar Tsarnaev's laptop showed his computer activity focused heavily on Facebook and a Russian version of Facebook.

The testimony is part of an effort by Tsarnaev's lawyers to show that Tamerlan was the mastermind of the bombings. The defense admitted during opening statements that Dzhokhar participated in the attack but said he fell under the influence of the radicalized Tamerlan.

Tamerlan died following a shootout with police days after the bombings.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

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Computer expert: Tsarnaev's brother searched for bomb parts
Accused Boston Marathon bomber Dzhokhar Tsarnaev (L) is shown in a courtroom sketch next to Judge George O'Toole on the first day of jury selection at the federal courthouse in Boston, Massachusetts January 5, 2015. O'Toole on Monday began the process of selecting the jury that will hear the trial of Tsarnaev, telling the first of some 1,200 prospects to read no more news accounts about the deadly blasts. Tsarnaev could get the death penalty if convicted of killing three people and injuring more than 260 others by detonating a pair of homemade bombs placed amid a crowd of thousands of spectators at the race's finish line on April 15, 2013. REUTERS/Jane Flavell Collins (UNITED STATES - Tags: CRIME LAW)
A memorial for the victims of the Boston Marathon bombings and its aftermath stands near the race's finish line, on the second day of jury selection in the trial of accused Boston Marathon bomber Dzhokhar Tsarnaev in Boston, Massachusetts January 6, 2015. The victims remembered are MIT police officer Sean Collier, Krystle Campbell, Lingzi Lu and Martin Richard. Tsarnaev could get the death penalty if convicted of killing three people and injuring more than 260 others by detonating a pair of homemade bombs placed amid a crowd of thousands of spectators at the race's finish line on April 15, 2013. REUTERS/Brian Snyder (UNITED STATES - Tags: CRIME LAW)
BOSTON - MARCH 9: An artist's sketch of Dzhokhar Tsarnaev hangs on the wall outside the Moakley courthouse for videographers to record during the Marathon bombing trial. (Photo by Lane Turner/The Boston Globe via Getty Images)
A courtroom sketch shows accused Boston Marathon bomber Dzhokhar Tsarnaev (C) sitting with his attorneys on the first day of his trail at the federal courthouse in Boston, Massachusetts March 4, 2015. REUTERS/Jane Flavell Collins (UNITED STATES - Tags: CRIME LAW)
A plaid backpack Is seen in this undated handout evidence photo provided by the U.S. Attorney's Office in Boston, Massachusetts on March 25, 2015. FBI Special Agent Kenneth Benton testified that he and fellow agents searched the landfill after a college friend of Tsarnaev's took the plaid backpack from the defendant's dorm room and tossed it into a dumpster. REUTERS/U.S. Attorney's Office/Handout FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS
BOSTON - MARCH 11: Members of the media film evidence from the Dzhokhar Tsarnaev Boston Marathon bombing trial on display at the Moakley Federal Courthouse in Boston on March 11, 2015 . (Photo by John Blanding/The Boston Globe via Getty Images)
BOSTON, MA - MAY 13: TV cameras line the entrance of John Joseph Moakley United States Courthouse as the Boston Bomber Trial enters jury deliberations in the sentencing phase of the trail on May 13, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev was found guilty on all 30 counts related to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries. (Photo by Scott Eisen/Getty Images)
BOSTON, MA - MAY 13: Members of the legal defense team for Boston Marathon bombing suspect Dzhokhar Tsarnaev, including William Fick (from left), Miriam Conrad, Judy Clarke and Timothy Watkins leave John Joseph Moakley United States Courthouse after the beginning of jury deliberations in the sentencing phase of the Boston Bomber Trial on May 13, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev was found guilty on all 30 counts related to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries. (Photo by Scott Eisen/Getty Images)
BOSTON, MA - MAY 13: Members of the public line up to enter John Joseph Moakley United States Courthouse as the Boston Bomber Trial is slated to start closing arguments on May 13, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev was found guilty on all 30 counts related to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries. (Photo by Scott Eisen/Getty Images)
BOSTON, MA - MAY 11: A protester holds up a sign outside of John Joseph Moakley United States Courthouse as the Tsarnaev defense nears its end of presenting case in sentencing phase of the Boston Bomber Trial on May 11, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev, 21, was found guilty on all 30 counts related to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries. (Photo by Scott Eisen/Getty Images)
BOSTON, MA - MAY 11: Sister Helen Prejean is surrounded by media after testifying at John Joseph Moakley United States Courthouse as the Tsarnaev defense nears its end of presenting case in sentencing phase of the Boston Bomber Trial on May 11, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev, 21, was found guilty on all 30 counts related to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries. (Photo by Scott Eisen/Getty Images)
BOSTON, MA - MAY 04: Members of the legal defense team for Boston Marathon bombing suspect Dzhokhar Tsarnaev, including Miriam Conrad, (from left), Judy Clarke and David Bruck arrive at John Joseph Moakley United States Courthouse as the sentencing phase in the Boston Bomber Trial continues on May 4, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev, 21, was found guilty on all 30 counts related to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries and his relatives are expected to take the stand to testify. (Photo by Scott Eisen/Getty Images)
Members of the legal defense team for Boston Marathon bombing suspect Dzhokhar Tsarnaev, including (L-R) David Bruck, Timothy G. Watkins and Judy Clarke leave John Joseph Moakley United States Courthouse as the sentencing phase In Boston Bomber Trial continues on April 27, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev, 21, was found guilty on all 30 counts related to to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries. (Photo by Scott Eisen/Getty Images)
Members of the legal defense team for Boston Marathon bombing suspect Dzhokhar Tsarnaev, including William Fick (L) and Timothy G. Watkins walk away from John Joseph Moakley United States Courthouse during the first day of the sentencing phase of the Boston Marathon Bomber Trial on April 21, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev, 21, was found guilty on all 30 counts related to to his involvement in the 2013 bombing, which related in three deaths and over 250 injuries.(Photo by Scott Eisen/Getty Images)
BOSTON, MA - APRIL 21: Media and police vechicles are reflected in the entranceway of John Joseph Moakley United States Courthouse during the first day of the sentencing phase of the Boston Marathon Bomber Trial on April 21, 2015 in Boston, Massachusetts. Dzhokar Tsarnaev, 21, was found guilty on all 30 counts related to to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries. (Photo by Scott Eisen/Getty Images)
BOSTON - APRIL 8: The jury found Dzhokhar Tsarnaev guilty at the Boston Marathon bombing trial at Moakley Federal Court. Bombing survivor Karen Brassard pauses as she answers a question outside the courthouse after the verdict. (Photo by John Tlumacki/The Boston Globe via Getty Images)
BOSTON, MA - APRIL 8: Dana Cohen, (from left), Carlos Arredondo, Karen Brassard, Liz Norden, Laurie Scher and Massport Fire Lt. Michael Ward at a press conference outside of John Joseph Moakley United States Courthouse following a verdict in the Marathon Bombing case on on April 8, 2015 in Boston, Massachusetts. Dzhokhar Tsarnaev, 21, was found guilty on all 30 counts related to his involvement in the 2013 bombing, which resulted in three deaths and over 250 injuries. (Photo by Scott Eisen/Getty Images)
BOSTON - MARCH 4: Opening statements in the trial of the Boston Marathon bomber took place at Moakley Federal Courthouse. A construction crew lowers a form to pour concrete in with the words 'Boston Strong' spray painted on it at a construction site directly across from the courthouse. (Photo by John Tlumacki/The Boston Globe via Getty Images)
BOSTON - MARCH 5: Boston Marathon bombing victim, Rebekah Gregory, right, arrived at Moakley Federal Courthouse in Boston, where the second day in the trial of Dzhokhar Tsarnaev got underway on March 5, 2015. (Photo by Wendy Maeda/The Boston Globe via Getty Images)
BOSTON, MA - MARCH 4: Joe Kebartas of South Boston protests the death penalty outside of the entrance to the John Joseph Moakley United States Courthouse during the first day of the Dzhokhar Tsarnaev trial on March 4, 2015 in Boston, Massachusetts. Dzhokhar Tsarnaev is charged with using a weapon of mass destruction in an attack on the April 15, 2013 Boston Marathon along with his brother Tamerlan, who was later killed during a shootout with police. (Photo by Scott Eisen/Getty Images)
BOSTON - MARCH 4: Jose Briceno, of Cambridge, Mass., protests outside Moakley Federal Courthouse, where opening statements began in the trial of Dzhokhar Tsarnaev on March 4, 2015. (Photo by Wendy Maeda/The Boston Globe via Getty Images)
A courtroom sketch shows Boston Marathon bombing suspect Dzhokhar Tsarnaev (R) during the jury selection process in his trial at the federal courthouse in Boston, Massachusetts January 15, 2015. Tsarnaev, who appeared in court on Thursday wearing a sport jacket and collared shirt, more formally dressed than in last week's appearances, and had trimmed his hair, is also charged with fatally shooting a university police officer three days after the bombing. He has pleaded not guilty. REUTERS/Jane Flavell Collins (UNITED STATES - Tags: CRIME LAW)
Fireworks are pictured in this undated handout evidence photo provided by the U.S. Attorney's Office in Boston, Massachusetts on March 25, 2015. The jury also saw a photo of a firework, with its powder removed, that was retrieved from a backpack found at a landfill south of Boston. FBI Special Agent Kenneth Benton testified that he and fellow agents searched the landfill after a college friend of Tsarnaev's took the plaid backpack from the defendant's dorm room and tossed it into a dumpster. REUTERS/U.S. Attorney's Office/Handout FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS
BOSTON - JANUARY 5: A heavy Coast Guard presence was seen in Boston Harbor by the Moakley Federal Courthouse for start of jury selection for the Boston Marathon bombing suspect Dzhokhar Tsarnaev trial. (Photo by David L. Ryan/The Boston Globe via Getty Images)
BOSTON, MA - JANUARY 04: A memorial stands at the site of the first bomb that went off in the Boston Marathon bombing of 2013 on January 4, 2015 in Boston, Massachusetts. Jury selection begins tomorrow in the case against Dzhokhar A. Tsarnaev, the suspected Boston Marathon bomber. Tsarnaev has plead 'not guilty' to 30 charges that could result in the death penalty if he is found guilty. (Photo by Andrew Burton/Getty Images)
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Lawyers for Boston Marathon bomber Dzkhokhar Tsarnaev started their case by trying to show that his older brother was the driving force behind the 2013 terror attack.

The defense called one of its first witnesses on Monday. A cell site analyst testified that Tsarnaev's cell phone was being used in southeastern Massachusetts - where he was attending the University of Massachusetts-Dartmouth - while pressure cookers were being purchased north of Boston in Saugus 2 1/2 months before the bombing. The analyst also said large quantities of BBs were purchased a little over a month before the attack in two Wal-Mart stores in New Hampshire, at a time when Tsarnaev's cell phone was again being used near the university.

Twin bombs filled with BBs and shrapnel exploded near the marathon's finish line on April 15, 2013. Three people were killed and more than 260 injured.

Prosecutors rested their case Monday after jurors saw gruesome autopsy photos and heard testimony from a medical examiner about the blast injuries that killed 8-year-old Martin Richard.

At least three jurors cried and wiped their eyes with tissues as they looked at photos of the boy. His parents watched somberly from the second row of the courtroom.

Dr. Henry Nields, chief medical examiner for Massachusetts, said Martin suffered injuries to virtually every part of his body, including lacerations of his liver, left kidney and spleen, broken bones and third-degree burns. His stomach also was ruptured.

Tsarnaev's lawyer told the jury during opening statements that he participated in the bombings but that his older brother, Tamerlan, was the mastermind behind the attack. Prosecutors believe the brothers were seeking retaliation against the U.S. for wars in Muslim countries.

The case by defense lawyers is expected to be relatively short. Once that is complete, jurors will deliberate on whether Tsarnaev is guilty of the 30 federal charges against him.

During the second phase of the trial, the same jury will hear more evidence to decide whether Tsarnaev, 21, should be put to death or should spend the rest of his life in prison.

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