Just as it closes the door on charges with British and U.S. authorities, the staff of a London-based brokerage firm may not be quite finished with its troubles on this side of the pond.

U.S. prosecutors are preparing to announce criminal charges against some past and present employees of ICAP PLC, a brokerage firm located in London, claiming they were involved in rigging the London interbank offered rate (LIBOR).

According to the Wall Street Journal (WSJ), which talked to people familiar with the case, the Department of Justice (DOJ) was planning to announce the charges against the ICAP employees as early as today — coinciding with British and U.S. authorities announcing their settlement with the company, which it had accused of similar malfeasance.

Under that settlement with U.S. Commodity Futures Trading Commission and the U.K.’s Financial Conduct Authority, ICAP is expected to pay a little less than $100 million in fines for its possible involvement in manipulating LIBOR and other benchmarks with bank traders.

But the criminal charges that may be announced today represent a landmark in the U.S.’s five-year investigation into LIBOR manipulation. The U.S. has only criminally charged two other people in the LIBOR investigation — two former Swiss bank employees back in December 2012.

According to the WSJ’s sources, ICAP is not expected to be charged at this time. ICAP is the fourth financial institution to be punished for its possible role in rate rigging. “The size of the settlement is considerably smaller than any of the past three, which totaled about $2.5 billion,” the WSJ reports.

Read more InsideCounsel stories relating to LIBOR: 

Barclays GC, CFO to resign

UBS AG to pay $1.5 billion for manipulating Libor

Homeowners accuse 12 banks of manipulating Libor