The father of a suspected terrorist arrested following recent attacks in New York and New Jersey says he voiced concern to the FBI about his son back in 2014 but to no avail.
Afghan-born Ahmad Khan Rahami, 28, was captured following a shootout with police in New Jersey on Monday.
An investigation was launched subsequently to see if he was radicalized during his visit to Afghanistan or Pakistan, Reuters reported.
"The investigation is active and ongoing, and it is being investigated as an act of terror," US Attorney General Loretta Lynch said in Lexington, Kentucky, on Tuesday.
Late on Saturday, an explosion in New York City's crowded Chelsea neighborhood left 29 people injured, while two other blasts in the suburban area of New Jersey caused no injuries.
Authorities took no action after reviewing a complaint by his father, Mohammad Rahami, two years earlier.
"I called the FBI two years ago," the father told reporters at the family's restaurant in Elizabeth, New Jersey.
His remarks were confirmed by authorities, saying he contacted the Federal Bureau of Investigation twice, once expressing concern that his son might be in touch with militants and the next time saying he was collaborating with criminals.
The suspected terrorist, who was injured along with two police officers upon being arrested, faces five counts of attempted first-degree murder and two second-degree weapons counts.
This is not the first time that the US police fails to obstruct an attack with the terrorist already on the radar.
Omar Mateen, a Daesh Takfiri affiliate who killed 49 people at a gay nightclub in Orlando in June, was interviewed twice by the FBI's Miami office, which found nothing during a 10-month investigation prior to the deadly attack.