Police are questioning four people following a shooting that critically injured a livery cab driver.

Investigators say the group was picked up just before 5 a.m. Friday and dropped off at Purlieu Gentlemen's Club on 36th Avenue in Astoria.

They then got into an argument inside the club and came back outside. That's when police say shots were fired, hitting 37-year-old Roberto Castillo in the head.

"I was on the corner, and the guy come out andthey shot the guy, and the guy run inside the restaurant. And after that, the police come," said one witness.

Witness: They fired for nothing.
Q: Do you feel like you're in danger every time you get behind the wheel because you don't know who you're picking up or dropping off?
Witness: Exactly. You never know what's going to happen. You pray for God nothing happen.

Castillo was taken to Elmhurst Hospital, where he's in critical condition.

The Taxi and Limousine Commission says Castillo was not a licensed driver but was working for a Bronx-based car service company.