WASHINGTON (AP) - The name of the dead Boston Marathon bombing suspect was included in a federal government travel-screening database in 2011 after the FBI investigated the man at Russia's request, two law enforcement officials briefed on the investigation told The Associated Press.

Tamerlan Tsarnaev's name was entered into the Treasury Enforcement Communications System, or TECS, as a routine procedure when the FBI looked into whether Tsarnaev was involved in terrorist activity, the law enforcement officials said on Monday, speaking on condition of anonymity because the investigation was ongoing.

TECS is the system used by US officials at the nation's borders to help screen people arriving in the US.

Tsarnaev died in a police shootout on Friday. His brother, Dzhokhar, was charged in his hospital room on Monday with using a weapon of mass destruction to kill, and he could get the death penalty. The brothers are accused of setting off two explosives that killed three people and wounded more than 200 others at the marathon.

Republican Sen. Lindsey Graham said on Monday that Tsarnaev's name was misspelled and Tsarnaev's correct name never went into the system.

According to one of the officials, an airline misspelled Tsarnaev's name when it submitted the list of passengers on Tsarnaev's flight to Russia in January 2012. Airlines are required to provide the US government with a list of passengers on international flights so the US can check their names through government databases, including the terrorist watch list.

But because Tsarnaev's name was misspelled, it was not matched with the 2011 entry in the TECS system, the official told the AP. However, the official said, even if his name had been spelled correctly and US officials recognised that Tsarnaev, the subject of a 2011 FBI inquiry, was on the flight, he would have faced no additional scrutiny because the FBI had by that time found no information connecting Tsarnaev to terrorism.

In 2011, Russia asked the FBI to look into Tsarnaev. The FBI was told Tsarnaev had changed drastically since 2010 as he prepared to leave the US to join unspecified underground groups. The FBI interviewed Tsarnaev and his relatives and didn't find any terrorism activity. FBI agents conducted an "assessment," an inquiry with a relatively low level of intrusiveness.

Agents carrying out assessments obtain publicly available information, check government records, peruse the Internet and request information from the public. Checking investigative leads through assessments can avoid the need to proceed to more formal levels of investigative activity.

In 2011, the FBI said, it checked US government databases and other information to look for derogatory phone conversations, possible use of online sites associating with promoting radical activity and associations with other persons of interest, Tsarnaev's travel history, plans and education.

The FBI did not find any incriminating information on Tsarnaev and a criminal case was not opened. The FBI shared its results with Russia in the summer of 2011. The FBI asked Russia for more information on Tsarnaev but never received any.

Russia did not volunteer any information to the U.S. about Tsarnaev's 6-month visit in Russia in 2012, the FBI said.

The law enforcement official said Tsarnaev did not use an alias when he traveled to Russia from the US.