The beggar was stationed outside a supermarket in the central Stockholm district of Södermalm on Saturday when the attack occurred, according to a police report.
Shortly before 1pm local resident Sophia Nyberg heard a loud bang from Mosebacke Square in central Södermalm. Ten minutes later a further explosion was heard a few blocks away.
"I was standing with my back to a woman who was begging when I heard a very loud bang. At first, I did not know what had happened, but saw that the woman stood up and was very shaken. As I understood it someone had approached and thrown a firecracker at her," she said.
"When I spoke to her she said she was okay, but she was crying and was clearly not okay at all. It was a really awful situation and I feel very sorry for this woman."
There was only a short delay before Sophia heard a third bang, also only a few blocks away.
"It must have been the same person," she said.
Police were alerted to the scene shortly after 1pm but have not been able to identify or detain any suspects for the attacks.
"We have received several calls about such events in this area. It looks as if this person or people have been to several places," said Kia Samrell at Stockholm police.