By Jana Winter

WASHINGTON (Reuters) -FBI investigations have been slowed or stalled by the second-longest U.S. government shutdown in history, leaving the bureau without funds to pay informants or make undercover drug or gun buys, gaps that an FBI spokesperson said are putting national security at risk.

The FBI does not provide detailed public information about how its $10.7 billion budget is spent and it is not clear how much of the total has been held up due to the shutdown, according to five current and three former FBI employees.

The shutdown, now in its 30th day, has frozen FBI funds used for operational travel, such as when an informant needs to travel to meet a drug supplier or boss or another investigative subject, the sources said. FBI employees are also without funds to travel

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