Boston Marathon bombings investigation moves forward

(CNN) -- Here's the latest on what we know about the Boston bombings:

-- The parents of Boston bombing suspects Tamerlan and Dzhokhar Tsarnaev will fly to the United States on Thursday, Anzor Tsarnaev told Russian state news agency Ria Novosti on Wednesday. The parents have agreed to assist in the investigation into the bombings, a police source said, Ria Novosti reported.

-- The body of Tamerlan Tsarnaev remains in the custody of the Massachusetts chief medical examiner, a spokesman for the medical examiner's office tells CNN. Terrel Harris also said the cause of Tsarnaev's death has yet to be determined.

-- Months after the FBI cleared now-deceased Boston Marathon bombing suspect Tamerlan Tsarnaev after a request from Russia to investigate him, the Russians also approached the CIA to look into Tsarnaev's shift toward Islamic extremism, a government official tells CNN. But the information provided by the Russians in November 2011 was "basically the same" information that had been given to the FBI, the government official said, adding that the communication sent to the CIA was a "warning letter."

-- Thirty-nine of the 264 people wounded in the marathon blasts remain hospitalized.

-- At least 14 people underwent amputations.

-- The name of one Boston Marathon bombing suspect was included in U.S. law enforcement and counterterrorism databases, but he was not on any watch list that would have prevented him from flying or required additional screening when he left or entered the country, intelligence and law enforcement officials said.

-- Human rights activist Kheda Saratova in Makhachkala, Dagestan, told CNN that the parents of the Tsarnaev brothers talked Wednesday with U.S. investigators and the Russian Federal Security Service.

-- Vice President Joe Biden spoke Wednesday at a memorial service for Sean Collier, the Massachusetts Institute of Technology campus officer who authorities say was killed by the suspected Boston Marathon bombers last week.

-- Biden referred to the suspects as "two twisted, perverted, cowardly, knock-off jihadis."

-- Citing terrorists in general, he said, "They do it to instill fear, to have us -- in the name of our safety and security -- jettison what we value most, and the world most values about us: our open society, our system of justice that guarantees freedom, the access of all Americans to opportunity, the free flow of information and people across this country, our transparency, that's their target."

-- The suspects in last week's bombings in Boston may have been planning to party in New York, that city's police commissioner, Ray Kelly, told reporters Wednesday, citing comments from the younger brother. "Information that we received said something about partying, having a party," he said.

-- Tamerlan Tsarnaev may have been "brainwashed" by a friend from Cambridge, Massachusetts named Misha -- an Armenian who had converted to Islam -- the dead man's uncle, Ruslan Tsarni, told CNN.

-- Elmirza Khozhgov, a former brother-in-law of the brothers, told CNN that the elder Tsarnaev introduced him to a man named Misha, but "I didn't witness him making him radical."

-- A spokeswoman for the Islamic Society of Boston told CNN that no one in the group's network appeared to have heard of the person named Misha.

-- The spokeswoman, Nichole Mossalam, said the group was prepared to hold a funeral for the dead brother, but had not been asked to do so. Several of the group's imams said they would not be comfortable presiding over a funeral for the elder brother, so the organization would likely ask a lay person to officiate, she said.

-- The surviving suspect, Dzhokhar Tsarnaev, has indicated to investigators that it was his brother, not any international terrorist group, who conceived the attack, a U.S. government source said.

-- The source said preliminary interviews with Dzhokhar Tsarnaev suggest the brothers were self-radicalized jihadists.

-- James Taylor sang at the memorial service at MIT, accompanied by the MIT Symphony Orchestra and a vocal ensemble from the university.

-- The suspects received welfare benefits as children, the state government says; Tamerlan received them for his family through last year.

-- Authorities reopened the site of the bomb blasts Wednesday to pedestrian traffic after replacing missing bricks and patching up concrete.

-- Dzhokhar Tsarnaev has cited the U.S. wars in Afghanistan and Iraq as motivating factors behind the attack, a U.S. government official said Tuesday.

-- Dzhokhar Tsarnaev remains hospitalized in fair condition.