A refugee from Iran has raised over $600,000 for the Pittsburgh synagogue where a gunman killed 11 people on Saturday.

On Sunday, Shay Khatiri, 29, started an online fundraiser to collect donations for the Tree of Life synagogue. As of Monday afternoon, he had raised over $640,000, far exceeding his expectations.

“I thought to myself, ‘Worst comes to worst, it will raise like $500.’ Which is better than nothing but it’s a little above that now,” he told WJLA.