Britain’s Serious Fraud Office (SFO), the agency in charge of prosecuting complex financial crime, has charged Barclays’ former rate submitter Jonathan Mathew, and former Barclays traders Stylianos Contogoulas, Jay Merchant, Alex Pabon, and Ryan Reich each with one count of conspiracy to defraud by manipulating U.S. dollar Libor rates between June 2005 and September 2007. The five men have pleaded not guilty.

Merchant, who was the line manager of Pabon and Reich, told the SFO in March 2014 when being interviewed as a suspect at the time in the case, that his top bosses at Barclays had known and approved the practice of submitting Libor requests to their London submitters, James Hines, prosecuting counsel for the SFO told Southwark Crown Court.

Mike Bagguley, Harry Harrison, and Eric Bommensath, the three bosses named by Merchant in 2014 will all appear as witnesses for the prosecution, Hines said.

“All three are alleged by Merchant to have known, approved and instructed the practice. All three deny this was an industry practice and they deny this practice was condoned or approved,” said Hines.

Bagguley, Harrison, and Barclays declined to comment. Bommensath did not immediately respond to a request for comment.

Merchant alleged in that 2014 interview that all three men already knew and approved of the practice of traders submitting requests to Libor submitters on the euro desk, said Hines.

London interbank offered rate (Libor) is a benchmark for about $450 trillion of financial contracts worldwide, from complex derivatives to student loans.

Merchant claimed that in late 2005 he had lunch with Bommensath, who left the bank in January 2015 but at the time was Barclays global head of fixed income, before he moved to New York to oversee the New York dollar swaps desk, said Hines.

During that lunch, Merchant claimed he was instructed by Bommensath to go out to New York to “teach these practices to make the New York swaps desk more profitable,” said Hines.

However in 2010, Merchant was interviewed by lawyers at Barclays regarding the Libor submitting process, in which he said that when he worked on the euro swaps desk before heading to New York, he had not made similar requests, said Hines.

He also said in that interview that it was his idea, when he moved to New York to begin a practice he characterized as “sharing cross-market information,” and instructed Pabon at the time to send requests to London submitters, said Hines.

“This time his account differed,” said Hines when referring to Merchant’s subsequent interview in 2014.

The SFO alleges the five men dishonestly agreed to procure or make submissions of rates into the dollar Libor-setting process which were false or misleading. Each count carries a maximum jail sentence of 10 years.

Defense lawyers have declined to comment and are expected to lay out their case on Friday following the prosecution’s opening statement. The high-profile trial, the third rate-rigging case brought by the SFO, is expected to last around 12 weeks.