There are several species of crocodiles around the world that are responsible for fatal attacks on humans, but most such attacks are by the Nile crocodile. The crocodiles that carry out the attacks are about 3 meters long, but they can be twice that size. It is thought that Nile crocodiles kill hundreds of people in poor areas of Africa every year. Crocodiles in Asia, Australia, and some tropical islands are also responsible for a number of fatal attacks. The salt-water crocs of Australia are known for the aggressiveness.I found a list of specific attacks on humans on this Wikipedia page (scroll down about 1/3):
I thought you might find the attack on the Japanese soldiers in 1945 particularly interesting.
Crocodiles hunt their prey by invisibly stalking them for hours. When the time is right. the huge crocs explode from the water and grab whatever body part they can get hold of, often an arm or leg. They then pull their prey under water. When the prey is dead, either from bleeding or drowning, the crocodile may bring it back to the surface and shake it so violently that it is torn to pieces. Other times, the crocodile rolls, claws, and rips while grasping the body. It will remove arms, legs, and head, then eats the pieces. After an attack, searchers may find small pieces of the body and torn up clothes in the water. In several cases of attacks by large crocs, pieces of body and clothing have been found in nearby tree branches because the crocodile shook the victim so hard.
Crocodiles also attack fro reasons other than food. A female will defend her nest. Males and females defend their territory. If surprised or frightened by a human, a croc will attack in self-defence. Sometimes people do very foolish things that can result in an attack.