Authorities in Nigeria’s capital, Abuja, say unidentified gunmen have attacked the offices of the Economic and Financial Crimes Commission (EFCC).
A source at the agency told the BBC that the gunmen shot at the empty offices early this morning, and left a letter addressed to one of the officials warning that they would kill him.
The source added that, while the motive was unclear, the agency suspects it could be linked to cases it is prosecuting in court.
No arrests have yet been made, according to Police Commissioner Spokesperson Wilson Uwujaren.
In June, a senior EFCC executive officer was shot at but survived in Port Harcourt, in the southern Rivers State.
The agency has been known to make daring raids to recover stolen money.
During one such operation in April, it uncovered $43m (£34m) in a flat in Lagos.