Final answer:
Henry Clay Frick used the Pinkerton Detective Agency as his private security force to suppress the strike at Homestead.
Step-by-step explanation:
Henry Clay Frick used the Pinkerton Detective Agency as his private security force to suppress the strike at Homestead. When the workers at Carnegie Steel Company went on strike in 1892, Frick hired three hundred Pinkerton detectives to protect the company property. However, the arrival of the Pinkertons led to a violent gunfight between them and the union workers, resulting in casualties on both sides.