LIVE: Press conference with bill Pulver, Madeline Pulver's father
An extraordinary breakthrough in an extraordinary case, a 50-year-old Australian man named as Paul "Doug" Peters has been arrested in the United States over the collar bomb hoax on Sydney schoolgirl Madeleine Pulver.
Mr Peters, who police say does business in Australia and the US, was arrested in Louisville, Kentucky about 5.30am AEST today (3.30pm Kentucky time on Monday) by an FBI SWAT team and two detectives from the NSW Robbery and Serious Crime Squad's Strike Force Haddon.
He was arrested by detectives from the NSW Robbery and Serious Crime Squad's Strike Force Haddon with assistance from the FBI in Louisville, Kentucky about 5.45am AEST today (3.45pm Kentucky time on Monday).
A heavily-armed FBI SWAT (Special Weapons and Tactics) team was present when the man was arrested at his home, Channel Seven reported.
Peters left Australia on August 8, but there is no known connection between him and the Pulver family, Channel Seven and Nine reported.
He remains in custody at FBI headquarters, local Kentucky television station WLKY reported.
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The ABC reported this morning that the FBI had the suspect under surveillance for some time.
NSW Police said they would apply for his extradition back to Australia when he faces court in the US.
NSW Police Assistant Commissioner Dave Hudson said the suspect had some connection to the Pulver family, but no "direct links".
"The ins and outs of motive are yet to be determined and that's part of our ongoing investigation," Mr Hudson said.
Mr Hudson said the man wasn't a suspect until he left Australia.
"We will allege through the courts ... [he] was responsible for entering the Pulver home and placing the device around [her] neck."
He would not outline exactly how police came to identify the man as a suspect.
"It's a fairly detailed chain of circumstantial evidence that has led us to making the arrest this morning."
Mr Hudson said the man had family in Australia and the US and did business in both countries.
He said police treated the bomb hoax as a "true offence" from the beginning.
No other people were being investigated at this point, he said.
NSW Police Commissioner Andrew Scipione said officers, including two from the NSW police force working in Louisville, had been preparing to make an arrest in recent days.
"Over the course of the last three or four days the NSW Police Force have been working very closely with the FBI in the US," he said.
It is understood the Pulver family will hold a separate press conference later this morning.
The FBI will also hold a media conference later on Monday evening Kentucky time, WLKY said.
The arrest came after reports a computer was seized by police on the NSW central coast over the weekend.
On Friday, police confirmed reports that investigators had a suspect, but had not spoken to the person yet. It followed a report Madeleine told police her attacker had "old, wrinkly eyes".
Shortly after the incident, it was also revealed that a long, typed note with strict instructions and signed by fiction character Dick Struan from the 1966 novel Tai-Pan had been pinned to Madeleine during her ordeal.
The fake bomb was attached to 18-year-old Madeleine by a balaclava-clad intruder in her family's home at Mosman on Sydney's north shore on August 3.
After 10 hours, the device around Madeleine's neck was found not to contain any explosives.
Her father, Bill Pulver, is the chief executive of Appen Butler Hill, a linguistic software company that specialises in voice recognition software.
The family was based in New York for a few years from 2002 when Mr Pulver was president and chief executive of NetRatings, an audience ratings company.
Channel Seven said police had been searching for the 51-year-old man since the early days of the case.
Investigators had a very strong circumstantial case, but no motive, the Seven report said.
Comment is being sought from the FBI.
- with AAP