This is in Swedish: https://www.svt.se/nyheter/lokalt/blekinge/danska-haverikommissionen-konstaterar-ingen-olycka-vid-fallet-fran-polenfarjan

Google translate:

It was not an accident but a deliberate act, the Danish accident commission stated, which is now closing its investigation into the deaths from the Polen ferry.

• We have installed surveillance footage, says investigator Morten Frederiksen to SVT.
  A seven-year-old boy and his mother died after they both ended up in the water while on the way by ferry to Karlskrona from Gdynia.
  At first an accident was suspected - but it is now dismissed by the Danish accident commission.

After its investigation, the Danish investigation states that it is instead a matter of deliberate handling, reports P4 Blekinge.

• It is correct, because we have now put surveillance footage that it was not an accident but a deliberate handling. Therefore, the police are taking over the case for the time being, says Morten Frederiksen, investigator at the Danish accident commission to SVT Blekinge.

Investigated as murder
It was on Thursday last week that the incident occurred. The deceased are Polish citizens and the ferry was on its way to Karlskrona from Poland.
Prosecutor Marie Lindström in Karlskrona has already started a preliminary investigation into murder. At the same time, the prosecutor’s office in Gdansk has opened an investigation into murder and suicide, according to the Polish television station Tvn24.

The ferry Stena Spirit, which sails under the Danish flag, is registered in Denmark and is therefore being investigated by the Danish accident commission.

The article says

In a brief statement Friday, Sweden’s Prosecution Authority said it has launched ”a preliminary investigation where the crime classification is murder, but there is no suspect in the case.”

Maybe that is what the person meant or referrence

Mum and son, 7, who fell off ferry treated as possible murder-suicide - Metro.co.uk