"The robbers weren't expecting to use this kind of transfer. It happened in the moment I think," Stefan Gustafsson, press officer for the police in west Sweden told Radio Sweden. "They didn't think a lot, I think."
The young man was surrounded by three masked robbers at 1:30 AM on Wednesday morning, beaten up and forced to send 2000 SEK over Swish.
Gustafsson said that police did not expect the investigation to take too long.
"It's quite easy because we have the account number where the money was transferred to, and of course we are interested in this account number and the person who has the account," he said.
He said investigators did not believe the robbers had been smart enough to transfer the money to someone unconnected to them.
Sweden is tipped to become the world's first cashless society, with a report last year predicting paper notes and coins could be obsolete as early as 2030.
Swish, a mobile phone cash tranfer launched in 2012 by six of Sweden's biggest banks, now has more than 5 million users in the country.
It can be used to transfer money between individuals or to pay for services just by tapping in a phone number.
Swish's press officer Per Ekvall argues preventing crime is one of its advantages.
"I think one of the big advantages with Swish is that it's traceable. When it's cash it's never traceable – but this is traceable."