How to use "professional" in a sentence

All the technicians wore white coats; they looked serious and professional

"You'll probably need professional help to catch him in one of his tricks."

"Then what did you mean when you said I'd probably need professional help to catch this creep?"

In freshly pressed slacks, a crisp blue shirt, a patterned tie, and a gray sports jacket, he might have been a professional hit man uncomfortably gotten up for the baptism of his Mafia don's grandchild

None of these people had to worry about professional killers, bizarre conspiracies, gas-company men who were not gas-company men, silencer-equipped pistols, exhumations

It was interesting that he, an ordinary soldier, seemed to have a much better understanding of the situation than I, a professional writer.