Not only that; in the version of the tale I read (amd am reciting from memory), the following happened.
Her husband had defeated some of the guys in question and demanded tribute from them, as was common in that time.
They agreed, when faced with his army, and he left.
Then he thought to himself "hey, maybe returning to them alone demanding more tribute is a good idea. I shall do that."
They killed him (and I believe sent his head to Olga).
She got a wee mad at that.
Spoilered for violence.
When ambassadors came to her to ask/demand she marries their leader (might have been the same bringing the message about his death, actually), she had a Russian bath prepared for them and had the house burned while they were in it.
Then more ambassadors came, with an army to "accompany" her to her would-be husband. She went along, insisting that a tenth of the army be comprised from her men.
Then she had her men make the others drunk and slaughter them in their sleep. I believe there was a pile of corpses involved.
Then she gathered a bigass army and moved against their city. Since most of their able-bodied men had recently been slaughtered, they quickly asked for the terms of surrender.
She spake thusly: "I shall spare the city, I demand only one sparrow and one pigeon from every household". And they marvelled at her magnimousity and agreed.
Then she had pieces of glowing timber bound to the feet of the birds, who flew home to their nests under the roofs of the wood-clad houses...