Two fishermen discovered a macabre in Svartån on Saturday when they took a human skull on the hook.
The police now suspect murder.
"They got a button down and the hook was a crane," Johan Tahlberg told the police.
The alarm came around 2 pm on Saturday.
– Two people are worried because they have found a crane in water. People were out of fishing, got a button down and a crane was on the hook, "said police spokesman Johan Tahlberg.
The police came to the place to capture the skull and interrogate the people.
The finding was made in Svartån between Västerås and Skultuna.
He's been investigating the murder.
– Since the start of the preliminary investigation, we have received many tools that we can work with.
The skull is examined
The skull has been transferred to Uppsala's forensic office for further investigation,
– At first contact with forensic science, they confirm that they are probably a crane. But we will do more research in the near future, we have not yet received a report.
In what condition was the skull when pulling, Johan Tahlberg can not answer.
"We do not have the knowledge we expect for forensic research.
How are you going with this?
"We will take further steps, I can not say so much, except that space is still interesting for research.
– We are not currently commenting on the location more than in Svartån.
Has the police blocked any field now?
– Not as I know right now.