Former Pakistan captain Ramiz Raja called Salman Butt a "liar" and ridiculed the suspended cricketer's defence against allegations of spot-fixing as a "big joke".
"Salman Butt's claims are a joke, a big joke. If you are implicated, you've got to come out straight away and say, 'I've not done this, I don't care what the allegations are, I'm not involved and that is the truth'," Raja told The News of the World, which has exposed the scam with a sting operation.
"He has not done that, he has come across as a big liar. I am so heavily and thoroughly disappointed by Pakistan's captain," he added.
Raja said for any match to be fixed, captain's involvement has to be there and Test skipper Butt cannot claim innocence in the face of some damning evidence produced by the newspaper.
"You look at match-fixing and the captain has to be crooked, they've got to be involved, along with some of the major players in the team, for it to happen," he said.
"It all depends on the captain. The way it was told in the paper '10th over, sixth ball' it actually did happen. It's up to the captain to ensure the bowler is still operating in the 10th over," he added.
Raja said he considered Butt a sensible cricketer but his actions have left him disappointed.
"I thought Butt was intelligent enough to understand the importance of leading Pakistan and setting an example.
"This is going to hurt Pakistan cricket. We have become a laughing stock. These players have brought shame on Pakistan's history. They have been caught in the act. Nothing can detract from that fact," he said.
Butt and pacers Mohammad Asif and Mohammad Aamir were suspended by the ICC after the sting operation, which showed a bookie boasting about how he bribed them to bowl no-balls during last week's Lord's Test against England.