Is my explanation and question natural?

From the news

Brenton Tarrant was charged with "engaging in a terrorist act", police said in a statement on Tuesday.
He is already facing charges of murder and 40 of attempted murder following the attack on two mosques in the South Island city on 15 March.

How did he tried to murder people 40 times?
Brenton Tarrant was caught for murdering and he already tired 40 times to murder a person. He also terrorised two mosques in the South Island city.