Los Angeles, Apr 5 (IANS): Police and the Federal Bureau of Investigation (FBI) are investigating the theft of as much as $30 million from a money storage facility in Los Angeles, according to local media.

Law enforcement sources told local KABC television station that the burglary happened at a GardaWorld facility in Sylmar, a suburban neighbourhood in the San Fernando Valley, on Easter Sunday.

The thieves broke into the facility undetected -- without setting off alarms -- by going through the roof and somehow getting into the money storage area, which may have been a vault, said the report, citing officials briefed on the investigation.

The company that owns the building did not discover the massive theft until Monday morning, the report added.

Law enforcement sources were quoted as saying by the major local newspaper, Los Angeles Times, that the break-in was among the largest burglaries in city history when it comes to cash, and the total surpassed any armoured-car heist in the city as well.

The burglary occurred Sunday night at the facility where cash from businesses across the region is handled and stored, said the report, adding that the break-in was described as elaborate and suggested an experienced crew of burglars who knew how to gain entry to a secure facility unnoticed.

The prior largest cash heist in Los Angeles was on September 12, 1997, with the robbery of $18.9 million from the former site of an armoured facility in the city, according to the report of the newspaper.