All three girls are of middle school age, write Kungsbacka-Posten.
The police suspect that there is a connection between the molestations.
– We have had some similar incidents in the recent past, and then we cannot rule out a connection, says Christer Fuxborg, press spokesperson for the police region West, to the newspaper.
In at least two of the incidents, the police have received similar descriptions of the perpetrator.
The latest molestation took place at a school on Wednesday.
On the previous occasions, in other places in the municipality, a perpetrator has tried to drag a girl with him – who, however, managed to get away.
The police are now also looking for similarities with events that happened in the past, and elsewhere in West Sweden.