The monitor you saw was probably a Water Monitor. They are one of the largest species.

Komodos are CITES restricted, so you will only see those in zoos.

However, monitors are great animals.....just because you can't imagine keeping a lizard as large as a dog.... it does not make those that keep them 'wish for death'.

They are no more dangerous than a large python as a pet....they just require more space to house and a responsible keeper.