Ahmad Khan Rahami, a 28-year-old naturalised American citizen of Afghan descent, was born in Afghanistan and majored in criminal justice at Middlesex County College in New Jersey, according to the FBI. Investigators are probing whether he was radicalized overseas before returning to the US in 2014.

In 2011, Rahami spent several weeks in Quetta, considered a stronghold of the Taliban and married a Pakistani woman, according to a law enforcement official who reviewed his travel and immigration record, news online reported on Tuesday.

Upon his return to the US, he had to go through secondary screening for visiting an area of Pakistan known for its Taliban presence. At that time, he told immigration officials he was visiting family and attending his uncle's wedding and renewing his Pakistani visa, officials said.

In 2013, Rahami went to Pakistan and remained there for a year. His brother also travelled to Pakistan around the same time and posted on Facebook that they heard seven bomb blasts over 24 hours at one point in Quetta, the report said.

Official said Rahami travelled by car to Afghanistan from Quetta. When he returned to the US, he was once again taken into secondary questioning but told officials he was visiting his wife, as well as his uncles and aunts. Each time Rahami was taken to secondary screening, he satisfied whatever concerns immigration officials had. He was questioned every time he returned to the US, as is standard procedure, but was not on the radar as someone who might have been radicalised, the official said.

He applied to bring his wife to the US in 2011 which was approved but it was unclear if she ever came to the US. In 2014, Rahami contacted Congressman Albio Sires' office from Islamabad for his wife's passport which was expired. Once it was renewed, she became pregnant and officials told her they would not give a visa until she had the baby.

A ruling later favoured the city, saying the restaurant was ‘disruptive in the city for many, many years’.

In a Facebook post, a family member asked for privacy. Rahami, who authorities said is ‘directly linked’ to the bombings in New York and New Jersey in which nearly 30 people were injured, was captured on Monday after a shootout and charged with five counts of attempted murder.