Two men and a woman forced their way into the old woman's apartment at 12:30 a.m., and stole an unknown amount of cash, gold, and documents.
The trio, for whom only a vague description has been obtained, first attacked the Slovakian live-in nurse, dragging her by her hair into the room of the elderly woman.
They bound and gagged both women with adhesive tape, slightly injuring the older woman on the lip. At gunpoint, they forced the old woman to hand over the key to a safe, which they proceeded to empty.
Police say that 'insider knowledge' cannot be ruled out in this brutal attack.
It is not the only home invasion robbery that has occurred near Innsbruck this year, as two armed men committed a similar crime in May.
The perpetrators are believed to be 30-40 years old. One of the men is said to have been wearing a pair of striking pale blue sports shoes with a grey pattern.
They spoke good German, according to the nurse. One of the men was armed with a small pistol.