Mazda 1997 626 brake light

I have a Mazda 1997 626 2.5 V6, I’ve noticed recently that after I turn the engine on, the brake light keeps on, this light is located at the left almost the top corner in the screen behind the steering.

I took the car to the mechanic and after he investigated the issue he said that it’s because of the hand-brake, he did something but still the light keeps on when I turn the engine.

Any idea or suggestion about what the issue is and what should I do.

Thanks