Bus Accident - No insurance

There was a horrible bus accident. Sadly, nobody survived the accident except a monkey that was on board and there have been no witnesses. The police try and investigate more however they get no results. At last, they fight to interrogate the monkey. The monkey looks to reply to their queries with gestures. Seeing that, they begin asking the queries.
The officer asks, 

"What were the people doing on the bus?" 

The monkey shakes his head in a very sad manner and starts dance around; which means the folks were dance and having fun. 

The chief asks, "Yeah, however what else were they doing?"

The monkey uses his hand and takes it to his mouth as if holding a bottle.
The chief says, "Oh! They were drinking, huh??!" 

The chief continues, "Okay, were they doing something else?" 

The monkey nods his head and moves his mouth back and forth, which means they were talking. The chief loses his patience, 

"If they were having such an excellent time, who was driving the stupid bus then?" The monkey cheerfully swings his arms to the edges as if grabbing a wheel.