Boston bombing suspect Dzhokhar Tsarnaev's medical condition has improved and is now being described as 'fair.'

The 19-year-old suspect was captured alive April 19 but was in critical condition after a self-inflicted gunshot wound to his throat. Since then, his condition had improved to 'serious' and the recent upgrade to 'fair' was announced April 23.

Since his capture, Dhokhar has been in hospital under heavy guard and had been charged with the crime of using weapons of mass destruction. The crime of this nature can lead to a death penalty.

He has been answering questions to the FBI and told them that the actions of him and his brother were carried out alone and their motivation came from the wars in Iraq and Afghanistan.

Investigators are currently questioning the brothers' parents who live in southern Russia.

According to reports, Tamerlan had previously been flagged as a possible Islamist radical back in 2011 and was even questioned by the FBI that year, but had since gone under the law enforcement's radar.

26-year-old Tamerlan Tsarnaev's wife Katherine Russell is also cooperating and answering questions.

No outside ties have been linked to the brothers and Dzhokhar admitted that the bombs were made after reading material from the controversial online Al-Qaida magazine Inspire, which previously ran a piece that taught readers how to 'make home-made bombs from your mom's kitchen' using pressure cookers.

Meanwhile, FBI has begun questioning members of a mosque that Tamerlan regularly attended.

Tamerlan attended the mosque in Cambridge, Mass., up until just weeks before the Boston bombings.

NBC reports that imams there told FBI that the 26-year-old had previously caused disturbances there and that they had even threatened to ban him from attending the services after a confrontation.

Mosque spokesman Yusaf Vali said they immediately called officials after they found out about Tamerlan's involvement in the crime. He called and told them: "Listen, we've got folks who knew him and if you need any information, we're here."'

In years leading up to the bombing, Tamerlan reportedly isolated himself and fell under the strong influence of a strict strain of Islam. He soon changed drastically, giving up boxing and stopped studying music and headed towards radicalism.

Three months before the Boston attacks, Tamerlan was reportedly kicked out of the mosque after a shouting match with an imam who used Martin Luther King Jr as an example of a man to emulate. The bombing suspect then accused him of being a hypocrite. Afterwards, he was asked to leave and was told that he needed to stay silent or will not be welcome there anymore.

One member of the mosque congregation, who identified himself as Muhammad, said he noticed he had anger inside.

The twin bombings at the Boston marathon finish line killed three innocent victims and injured over 200 people. The aftermath was that of a warzone and many had their limb(s) amputated. "He had anger inside," he told LA Times. "I can't explain what was in his mind."

Tamerlan was killed in a police shootout hours after he and his brother were identified as the bombing suspects and killed a police officer at the MIT campus April 18. Dzhokhar managed to escape but within 24 hours of his brother's death, Dzhokhar was finally captured alive but in critical condition hiding in a boat behind the now-infamous residence of 76 Franklin St. in Watertown, Mass.

The whole town had been on lockdown before Dhokhar's capture and he reportedly shot himself in the mouth to avoid being captured alive.

Authorities have reported that Dzhokhar's condition has been upgraded from critical to serious and finally he is in a fair condition. He was roused just days after his capture to be charged for the crime of using a weapon of mass destruction.

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