Robber Flies or Assassin Flies belong to the Asilidae family of invertebrates.
https://en.wikipedia.org/wiki/Asilidae has a lot of information about these flies. They are aggressive and predatory feeding on other insects, often catching their prey in flight. Asilidae are from the order of Diptera.
Robber Flies live in urban areas, forests and woodlands. They have strong claws to catch their prey and then they inject a powerful poison to paralyse the victim.
Robber Flies more closely resemble wasps or bees than common flies. They do not seek out humans as they don’t seek out blood like a mosquito.
In turn they need to watch out for insect-eating birds and spiders.
Robber Flies lay their eggs in the soil or in some decayed wood.