It was revealed later that it was an electrical fire. The smell was very familiar to me. It smelled like a burnt capacitor or semiconductor. I can still smell it. I'm sure we will continue to smell it until the clean up takes place.
The fire was in the apartment on the diagonal corner of our floor. The fire department had the electric company kill the power to that apartment because they were worried about the wiring there. The Fire Chief told the tenants that the power had been shut off and the apartment would remain dark. He also told tenants that there will be an investigation.
Luckily it was contained to that one apartment. The fire was actually put out by the fire extinguisher that was in the hallway, so it didn't get out of hand.