It was still safe even then as long as you stayed in central Stockholm and away from certain suburbs outside of the city. There was some petty crime in the very center of the city but it was mainly pick pockets or stuff like that.
The Swedes let their kids take public transportation to school, etc. alone regularly as did the expats. By the end of my stay there, I routinely let my kids take the trains and buses (within the city) to lessons, friends, shopping, etc. alone.
I didn't get out of central Stockholm much and I would go weeks without seeing a Muslim, Somali, etc. A few here and there at T-centralen but nothing too remarkable.
Even with this massive change in a relatively short period of time, our Swedish friends are still in denial that this is happening. The last conversation I had, about two weeks ago, our friend said, "Normal Swedes aren't seeing any of this"
My daughter (now 19) wants to do study abroad and, naturally, wanted to go there. I said, "no frikking way". I said, your choices are Singapore, Hungary, Poland or Czech Republic. (:
Stockholm may remain nice Nordic European for awhile. But as I’m sure you’re aware parts of Malmö have become a cold climate outpost of the Caliphate. As the first major stop for trains coming out of Denmark it’s the logical location for a beach head invasion from the Continent. And that’s what this is.