According to an AP source, Russian agents placed Tamerlan Tsarnaev under surveillance during a six month visit to Russia last year.

A security official with the Anti-Extremist Agency in Russia told AP that Russian agents were watching Tamerlan Tsarnaev while he visited Russia. The agents searched for two days to find Tamerlan when he disappeared following the death of a Canadian extremist in July of 2012. The extremist had joined the Islamic insurgency in the region. 

Security officials suspected ties between Tsarnaev and the Canadian – an ethnic Russian named William Plotnikov – according to the Novaya Gazeta newspaper, which is known for its independence and investigative reporting and cited an unnamed official with the Anti-Extremism Center, which tracks militants. The newspaper said the men had social networking ties that brought Tsarnaev to the attention of Russian security services for the first time in late 2010.

After Plotnikov was killed, Tamerlan left “suddenly” to return to the US–without his passport, one of the reasons he traveled to Russia in the first place.  “The official said his sudden departure was considered suspicious.”

Plotnikov was brought in for questioning in Dagestan in December 2010 under suspicion of having ties to Islamic militants. Novaya Gazeta reported that while interrogated, he was forced to hand over a list of social networking contacts that were located in the US and Canada. “Tsarnaev’s name was on that list, bringing him for the first time to the attention of Russia’s secret services.” After Tamerlan’s social networks were examined, the Russian Secret Service notified the FBI.

After losing track of Tamerlan, Russian agents contacted his father who told them that Tamerlan had left Russia. It was later determined that Tamerlan had flown to Moscow on July 16 and arrived in the US the day after.

The official with Russia’s Anti-Extremism Center said Tsarnaev was filmed attending a mosque in Makhachkala whose worshipers adhere to a more radical strain of Islam. The official would give no further details about what the Russian security services knew about Tsarnaev’s activities in Dagestan or about any possible connection to Plotnikov.

Novaya Gazeta reported that Tamerlan was “seen in the company of Mahmud Nidal – a man who was both Palestinian and Kumyk, one of the dozens of ethnic groups living in Dagestan – and who was believed to have ties to Islamic militants in the southern Russian region.” 

The FBI investigated Tamerlan in the US, but found no evidence of terrorism.