Justin Sebik admitted using intimidation tactics

He was also heard to say: "Hang on, I'm going to slash your throat. Would you get mad if I just killed you?"

Background checks after the incident found the 26-year-old bartender had been arrested twice previously, although all charges were dropped.

Bayonne Municipal Court, in Sebik's hometown, confirmed he had been arrested for assault in June, 1996.

He was also charged with two counts of assault and two thefts in April 1997.

'Professional'

No details of the cases have been released but all charges were dismissed in December 1997.

Big Brother network CBS has defended allowing Sebik into the house, saying it had carried out a thorough check before the show began, but the arrests were not disclosed by the courthouse.

Bosses promised a more exciting second series

Spokesman Gil Schwartz said: "This was a professional background check.

"It was done well. We have full confidence in the process.

"Clearly, we're still working on making sure the process is infallible."

Following the knife incident Sebik insisted that he had only been joking.

But CBS bosses already had an uneasy feeling about the contestant's behaviour.

He was warned about derogatory comments towards women after he got into an argument and admitted using intimidation tactics.

CBS decided not to screen the eviction but explained to viewers the reason he was no longer there.

The US Big Brother, which sees 12 strangers living together for the chance to win $500,000 (�355,300), is three weeks into its second series.