Two men of interest has been confirmed by the FBI for the Boston Marathon bombings that killed 3 and left 176 injured on Monday.

Homeland Security Secretary Janet Napalitano confirmed that FBI wants to interview two men seen in one of the videos taken of the Boston Marathon.

However, Napalitano noted that they were not being treated as suspects, telling the House Homeland Security Committee Thursday that "there is some video that raised question" of two men.

FBI still has not confirmed whether the terror attacks were from domestic or foreign terrorists.

Meanwhile, a memorial service for victims of the bombing is underway at the Cathedral of the Holy Cross in Boston.

The interfaith memorial started at 11a.m. ET and President Obama along with his wife Michelle are in attendance.

President Obama addressed the nation in a press conference immediately after the attacks, saying: "We will find out who did this; we'll find out why they did this," said the president from the White House. "Any responsible individuals, any respon­sible groups will feel the full weight of justice."

Innocent victims 8-year-old Martin Richards, 29-year-old Krystle M. Campbell, and Boston University grad student Lu Lingzi lost their lives in the horrific bombings. 17 of those injured remain in critical condition.

Two bombs went off almost simultaneously 4 hours and 10 minutes into the race. The aftermath of the bomb was the scene of warfare, as blood and limbs were scattered everywhere.

A video believed to be a suspect dropping a duffel bag near has been captured by CCTV surveillance cameras near the Lord and Taylor department store in Boston.

Despite video footage, no suspect has been arrested or identified as of yet.