The Libor affects how much interest ordinary people pay on everything from credit card debt to home mortgages and student loans.
Barclays was fined $450 million by British and American regulators last month after admitted some of its trading desks purposely underreported its interest rates.
Diamond said he hoped the decision on his pay and bonuses "will help close this chapter and allow Barclays to move forward and prosper."
Agius' evidence follows that of Bank of England's deputy governor Paul Tucker Monday, in which he denied being pressured by politicians to ensure Libor rates were lowered. He also denied pressuring Barclays to lower its rates.
Diamond last week said he was "sorry, I'm disappointed and I'm angry" about the rate-fixing. "This was wrong and I'm not happy about it, but we put all the resources we could to make sure it was dealt with."
He said also "this doesn't represent the Barclays that I know and I love." Diamond blamed the wrongdoing on 14 traders out of "a couple thousand."
A report from the UK's Financial Services Authority concluded the rate-fixing scandal was of the "utmost seriousness."
Between 2005 and 2009, when Diamond was in charge of the investment branch of Barclays bank, traders were influencing the pricing of rates which impact up to $800 trillion of securities.
E-mails revealed as part of the rate-fixing investigation showed traders were seeking beneficial rates for their trading positions.
During the credit crisis of 2007 and 2008, Barclays' high Libor postings came under scrutiny and the bank, concerned about "unfounded negative perceptions," lowered its Libor submissions, according to Barclays notes to the Treasury Committee.