The VG Resource

Indeed they actually did, while I was playing the game. A lot of the sounds sounded familiar to me.

For example one of the sounds used for the black guy saying "Hey!" when you tap on him
is stolen from a game called  Ultimate Muscle: Legends vs. New Generation, and it's King Muscle's voice clip.

The next few sounds, is when you tap on the shirtless gangster guy.
His sounds were stolen from POSTAL 2 or 3, and the character sounds like POSTAL Guy