LONDON (REUTERS) - The UK National Crime Agency (NCA) is examining accusations that an employee leaked information to a suspect for money, undermining a probe into a network of insider trading suspects in Europe, the Wall Street Journal reported on Thursday (Dec 27).

The NCA, which usually focuses on tackling serious and organised crime, is investigating whether a government translator with access to wiretap recordings tipped off the target of an insider-trading investigation, the Journal reported, citing people familiar with the matter.

Britain's markets watchdog, the Financial Conduct Authority (FCA), declined to comment, citing reporting restrictions.

The NCA did not immediately reply to Reuters' requests for comment, sent outside of business hours. An NCA spokesman told the WSJ that the agency does not routinely confirm or deny the existence of investigations.

The allegations stem from an investigation started in 2013, which included monitoring a network of people suspected of using illegal tips to trade stocks, the report said, citing sources.

The investigation has led to at least one prosecution.

The report cited a letter suggesting there was a joint investigation by the NCA and FCA into trading activities of the suspects.

One of the suspects had "three people working for him at the agency," according to the letter cited by the Journal, referring to the NCA.

Another suspect said the accused traders could pay off NCA officers assigned to the case by sending money to a bank account in Macau, according to the report.

Neither the name of the translator nor the exact time of the leaks could be learnt by the Journal.