Rep. Peter King (R-N.Y.), the former chairman of the House Committee on Homeland Security, said Sunday that he did not believe the suspects in last month's Boston Marathon bombings acted alone.

"It's very difficult to believe these two could have carried out this level of attack with this level of sophistication and precision acting by themselves, without training overseas or having at least facilitators at home," King said.

King, who sits on the Permanent Select Committee on Intelligence, said it appeared from the effectiveness of the dual bombings that Tamerlan Tsarnaev and his younger brother, Dzhokhar, had some help.

"To me, there had to be assistance and that's why the FBI, I think, is going after this so vigorously," King said.

The New York congressman said that in an upcoming House hearing examining the marathon attack, he hoped to highlight FBI agents' inability or unwillingness to interview members of Tamerlan Tsarnaev's mosque after a tip from Russian intelligence that he might have become radicalized. 

"Because of political correctness, I understand that the FBI was not able to talk to anyone in the mosque to find out whether or not if there were any conditions to find out if he was radicalized," King said.

King also said he would press the Department of Homeland Security to address the "inexcusable" system under which information about student visas was not properly shared between agencies. According to King, officials have said they don't have the technology to marry separate systems that track whether someone entering the country has a student visa and whether or not it remains valid.

"Each of them has a separate list. One has the I-20 form that shows whether or not the student is compliant, the other has the student visa. Homeland Security should have been work[ing] more effectively toward making this technologically feasible," King said.

The Department of Homeland Security announced over the weekend that border security agents must now check that foreign students entering the country have a valid visa. Azamat Tazhayakov, who was arrested last week and accused of removing a backpack containing fireworks from Dzhokhar Tsarnaev's apartment, did not have valid documentation when he returned to the U.S. in January, but was waved through by border agents who did not have access to the database from Homeland Security. 

"Everyone coming in with a student visa, my understanding is gonna be stopped and checked and examined at the airport, which might cause longer lines but I think is something we have to do," King said.