Islamabad, Feb 2 (IANS): A parcel delivered last year to Pakistan Prime Minister Yousuf Raza Gilani's residence contained deadly anthrax, laboratory tests revealed, much to the shock of his staff.

The security staff at Gilani's residence Wednesday were shocked to learn that a parcel received in October last year carried deadly anthrax, reported Dawn.

Sleuths have found out that consignment's origin is in Jamshoro district in Sindh province.

An official said that a female associate professor at Sindh University Jamshoro is suspected of dispatching the parcel to the prime minister's official residence.

"...laboratory tests have confirmed that it was anthrax...," the official was quoted as saying.

When the parcel was received in October last year, the security staff posted at the outer gate of the Prime Minister House spotted a powder-like material in the parcel and informed their superiors who sent it for a laboratory test.

The official said that all parcels are checked at variously levels.

The heavily-guarded official residence of the prime minister has multiple security cordons.