They'd probably offer a huge reward for any information or something like that. Not like anyone would be dumb enough to double cross the Joker. Even ten grand wasn't enough to start over where the Joker couldn't find you.
Apparently, he was crazy enough to kill his own henchman because they dared to take off Batman's hood. Two of them managed to get out, one ran to the police and the other left Gotham. The one that ran to the Police died of a "heart attack" on the toilet before being interrogated. He was only twenty-four and seemed healthy enough.