(CNN) -- Here are the most recent developments in the investigation into the April 15 Boston Marathon bombs:
-- The death certificate for Boston bombings suspect Tamerlan Tsarnaev, who died April 19 after a shootout with police, says he died of "gunshot wounds of torso and extremities" and "blunt trauma to head and torso," according to Peter Stefan, the owner of the Graham, Putnam & Mahoney Funeral Parlors, which currently holds his body.
Previously reported developments:
-- Of the 264 people injured in the Boston Marathon bombings, 12 people, including one in serious condition, remained hospitalized Friday, according to a CNN count.
--The Department of Homeland Security has ordered U.S. Customs and Border Protection agents to verify "effective immediately" that every foreign student who wants to enter the United States has a valid student visa, a U.S. government official told CNN on Friday.
-- Explosive residue has been found at the Cambridge, Massachusetts, home that suspect Tamerlan Tsarnaev shared with his wife, Katherine, and their young daughter, a source briefed on the Boston bombing investigation told CNN Friday. The source said residue samples tested positive in at least three areas: the kitchen table, the kitchen sink, and the bathtub.
-- Federal agents, state troopers and local officers were searching areas in and around Dartmouth, Massachusetts, on Friday as part of the investigation into the Boston Marathon bombings, the FBI said. "There is no threat to public safety," the bureau said.
-- The funeral for Boston Marathon bombing suspect Tamerlan Tsarnaev will be held in Worcester, Massachusetts, the mayor's office in that city said Friday.
-- Tamerlan Tsarnaev's body was claimed Thursday by one of his uncles, Ruslan Tsarni, who lives in Maryland, according to a family spokeswoman.
-- The Massachusetts chief medical examiner's office said the cause of Tamerlan Tsarnaev's death will not be made public until the death certificate is filed with Boston's city clerk's office.
-- The bombs used in the Boston Marathon attack were built in the apartment that suspect Tamerlan Tsarnaev shared with his wife and child, according to a U.S. law enforcement official briefed on the investigation.
-- Suspects Tamerlan and Dzhokhar Tsarnaev initially planned to carry out an attack on July 4, but their bombs were ready earlier than they expected and they decided to move up the date, a U.S. law enforcement official told CNN on Thursday.
-- A laptop computer belonging to suspect Dzhokhar Tsarnaev was turned over to the FBI by one of Tsarnaev's friends who has been charged with obstructing justice, Dias Kadyrbayev's lawyer told CNN on Thursday. A law enforcement source confirmed the attorney's account. He and another friend, Azamat Tazhayakov are accused of hiding it and other evidence from investigators.
-- A federal law enforcement official told CNN the charge of conspiring to obstruct justice relates to their moving things from Dzhokhar Tsarnaev's dorm room and throwing them into a dumpster. The source said the objects disposed of included fireworks inside backpacks. The trash bin subsequently was taken to a nearby landfill. Authorities carried out a two-day search of the landfill in New Bedford late last week.
-- The Kazakhstan Foreign Ministry said it was offering consular services to Kadyrbayev and Tazhayakov. "We would like to emphasize that our citizens did not receive charges of involvement in the organization of the Boston Marathon bombings. They were charged with destroying evidence," the ministry said in a statement.
-- Katherine Russell, widow of Tamerlan Tsarnaev, spoke to her husband after his picture appeared on national television as a suspect, two sources familiar with the investigation told CNN on Wednesday. The nature of the conversation remains under investigation, but the sources said there was some concern that Russell spoke with her husband but did not call authorities who were still seeking to identify the men in the photos.
-- Authorities said Wednesday that three of Dzhokhar Tsarnaev's friends -- Kazakh nationals Kadyrbayev and Tazhayakov and U.S. citizen Robel Phillipos -- were arrested in connection with the Boston Marathon bombings. The three men are accused of helping Tsarnaev after the April 15 attack, according to federal prosecutors.
-- About a month before the marathon attack, Dzhokhar Tsarnaev had told Kadyrbayev and Tazhayakov "that he knew how to make a bomb," according to an FBI affidavit recounting the charges. Kadyrbayev told investigators that Tsarnaev "appeared to have given himself a short haircut" two days after the bombings.
-- According to the affidavit, when the FBI on April 18 released photographs of bomb suspects later identified as Dzhokhar Tsarnaev and his older brother Tamerlan, Kadyrbayev texted his friend Dzhokhar to tell him "he looked like the suspect on television." Tsarnaev texted back "lol" and added, "come to my room and take whatever you want." Phillipos, Tazhayakov and Kadyrbayev went to the room, where Kadyrbayev noticed a backpack containing fireworks that had been "opened and emptied of powder," according to the affidavit.
"Kadyrbayev knew when he saw the empty fireworks that Tsarnaev was involved in the marathon bombing," the affidavit states.
-- Phillipos is charged with "willfully making materially false statements to federal law enforcement officials during a terrorism investigation," according to the complaint.