A domestic dispute in 2014 triggered FBI scrutiny into New York-area bombing suspect Ahmad Khan Rahami.
A law enforcement official said that Rahami's father, Mohammad R. Rahami, had called New Jersey police over the dispute involving his son but later retracted his complaint.
When these types of complaints come in, they usually go into the FBI's Guardian Threat Tracking System, which prompts a limited level of investigation and surveillance.
In a statement, the FBI said that it "conducted internal database reviews, interagency checks, and multiple interviews, none of which revealed ties to terrorism."
According to The New York Times, which first reported the FBI contact, Mohammad Rahami told local police he suspected his son might be involved in terrorism.
The newspaper interviewed the father, who said:
" 'Two years ago I go to the F.B.I. because my son was doing really bad, O.K.?' he said. 'But they check almost two months, they say, 'He's O.K., he's clean, he's not a terrorist.' I say O.K.'
"He added: 'Now they say he is a terrorist. I say O.K.' "
According to court documents, prosecutors wanted to charge Rahami over that domestic dispute. The documents show prosecutors presented a grand jury with aggravated assault charges, arguing that Rahami allegedly stabbed a relative named Nasim Rahami in the leg. The grand jury, however, found there was not enough evidence to indict Rahami.
Talking to reporters outside his home, Mohammad R. Rahami said he had called police on his son because he "stabbed my son" and "hit my wife."
"I put him in jail two years ago," Rahami said.
Authorities suspect Ahmad Khan Rahami is responsible for the weekend bombings in New York and New Jersey that left dozens injured. Rahami was taken into custody Monday after a short, but intense manhunt and was charged later that day with five counts of attempted murder of a law enforcement officer and two counts related to possession of a weapon.
The investigation is now focused on motive.
Quoting two law enforcement and intelligence sources, NPR's Dina Temple-Raston sends us this update on the investigation:
— Rahami started talking to law enforcement this morning. It's unclear how helpful he is being. It's also unclear whether he was read his Miranda rights — it appears he initially talked without having been read his rights, which happens often in terrorism cases.
— Officials are trying to determine whether Rahami's wife is still in the country.
— Two sources tell NPR that a note mentioning the Boston Marathon bombers and radical cleric Anwar al-Awlaki was found near an undetonated bomb found on West 27th Street in New York City.