U.S. Investigators Interview Alleged Bombers' Parents in Dagestan

MAKHACHKALA, Dagestan April 23, 2013 -- A team from the U.S. embassy in Moscow is in Dagestan today to interview the parents of two brothers suspected of planting bombs at last week's Boston marathon, ABC News has learned.

But the mom said today her sons were only guilty of being Muslim.

According to an embassy official, the Russian government is cooperating with the FBI's investigation.

This confirms what the suspects' mother told ABC News in a phone interview on Monday, that she and her husband expected to be interviewed by American and Russian officials soon. She suggested that might delay their plans to travel to the United States.

The mother, Zubeidat Tsarnaeva, left her house accompanied by her brother-in-law and tried to evade the crowd of television cameras that followed her. She ignored questions from reporters, but when ABC News asked her "What did your son do?" Tsarnaeva turned and shouted "My son just was Muslim. My son was Muslim, that's it."

Tsarnaeva and the relative got into a taxi and sped away, ending her first appearance in public since Friday's bloody standoff with police that left her older son Tamerlan Tsarnaev, 26, dead and ended when his younger brother Dzhokhar Tsarnaeva, 19, was captured alive.

On Friday, President Obama spoke on the phone with Russian President Vladimir Putin and they agreed to continue counterterrorism cooperation.

Investigators want to know what Tamerlan Tsarnaev, the eldest brother, did in Dagestan, a restive region in southern Russia that is home to an Islamist insurgency, during a six month visit in 2012. Specifically they want to know if Tamerlan, who began linking to Islamic extremist web videos on YouTube after the trip, met any radicals or militants during his trip.

The head of Russia's Interpol branch said Monday they were not searching for anyone new in connection with the Boston bombing.

"We are not searching for anyone, we have received no tip-offs," he said, according to RIA Novosti.

RIA Novosti also reported investigators in Dagestan saying they had no indication the suspects had ties to militants there.

"If this young man had indeed been mixed up in something, and if his activities undermined the country's security, he would not have left the country," an official was quoted saying.

Their mother told ABC News Monday that she urged Tamerlan to embrace Islam in 2008 after she became concerned about his drinking, smoking and women. She said she also became more religious and started wearing a head covering.

Her growing religious beliefs also took a toll on her marriage. She said her husband demanded a divorce over two years ago, in large part because of her new views on religion.

Other family members said they never saw signs Tamerlan had become radicalized during his stay in Dagestan. One relative, however, said an uncle had kicked him out, upset by his increasingly extreme religious views.