(MAKHACHKALA, Dagestan) -- A team from the U.S. embassy in Moscow is in Dagestan Tuesday to interview the parents of two brothers suspected of planting bombs at last week's Boston Marathon, ABC News has learned.
Still, Zubeidat Tsarnaeva, thie suspects' mother, said on Tuesday that 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.
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 the 26-year-old, who began linking to Islamic extremist web videos on YouTube after the trip, met any radicals or militants during his visit.
The head of Russia's Interpol branch said on 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.
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