Marathon bombings mastermind Tamerlan Tsarnaev was living on taxpayer-funded state welfare benefits even as he was delving deep into the world of radical anti-American Islamism, the Herald has learned.

State officials confirmed last night that Tsarnaev, slain in a raging gun battle with police last Friday, was receiving benefits along with his wife, Katherine Russell Tsarnaev, and their 3-year-old daughter. The state’s Executive Office of Health and Human Services said those benefits ended in 2012 when the couple stopped meeting income eligibility limits. Russell Tsarnaev’s attorney has claimed Katherine — who had converted to Islam — was working up to 80 hours a week as a home health aide while Tsarnaev stayed at home.

In addition, both of Tsarnaev’s parents received benefits, and accused brother bombers Dzhokhar and Tamerlan were recipients through their parents when they were younger, according to the state.

The news raises questions over whether Tsarnaev financed his radicalization on taxpayer money.

Relatives and news reports have indicated that Tamerlan Tsarnaev’s descent into extremist Islam began around 2008 or 2009, when the ethnic Chechen met a convert identified only as “Misha,” began to become more devout, and sought out jihadist and conspiracy theorist websites, and the rabidly anti-Semitic propaganda tract, “The Protocols of the Elders of Zion.”

In 2009, he was quoted in a photo essay as saying, “I don’t have a single American friend, I don’t understand them,” adding that he believed Americans had lost their “values.”

His uncle Ruslan Tsarnaev said it was around that time his nephew gave up drinking and was devoting himself to “God’s business,” while Tamerlan’s mother, now wearing a hijab — an Islamic headscarf — began relating conspiracy theories about the Sept. 11, 2001, terror attacks to her cosmetology clients that she said her son had told her.

In early 2011, Tamerlan Tsarnaev first came to the attention of the FBI when the Russian FSB intelligence service contacted the U.S. agency to warn that he was suspected of being a dangerous radical and sought information.

“The request stated that it was based on information that he had changed drastically since 2010 as he prepared to leave the United States for travel to the country’s region to join unspecified underground groups.” The FBI reported finding no “terrorism activity.”

In mid-2011, he was being monitored by the FSB, apparently prompting the FBI contact, ahead of his six-month trip home to Dagestan in 2012, where Time magazine reported he is believed to have attended a notorious radical mosque.

The state did not say when the Tsarnaevs began receiving benefits. But Health and Human Services spokesman Alec Loftus said the Tsarnaevs “were not receiving transitional assistance benefits at the time of the incident,” a reference to the marathon bombing that killed three and injured 260.

Loftus declined to specify what kinds of benefits and the amount of benefits the family received.

Their taxpayer-funded status came to light last night after repeated calls and emails to welfare officials from the Herald. They refused to comment throughout the day, but pressure mounted last night when the Herald started asking lawmakers whether the Department of Transitional Assistance should release the information.