8 He waits in ambush near settlements; he kills the innocent in secret places. His eyes pursue the helpless; 9 he hides in secret like a lion in a bush. He hides in order to seize a victim; he seizes a victim and drags him in his net. 10 So he is oppressed and smashed up. Helpless people die because of the wicked one’s strength.
The psalmist is talking about the kind of person who exploits the helpless, even causing their death for his own selfish purposes.
He calls on God to rescue the innocent victims of the exploiters. In a perfect world, we could depend on just laws and government enforcement of those laws to prevent violence towards the innocent. But the psalmist didn’t live in a world like that, and neither do we.