MINNEAPOLIS (AP) — Investigators have not been able to determine what caused a Valentine's Day fire that killed five children in a north Minneapolis duplex.

A report by the State Fire Marshal Division says the fire started on the second level, but a cause could not be determined.

The Feb. 14 fire killed five children ages 18 months to 8 years old. The children's father, Troy Lewis, survived as did two other children.

The Star Tribune reports the family is preparing to sue the property's owner for wrongful death. The family's attorney, Jeffrey Sieben, says the lawsuit likely will name property owner Paul Bertelson or his company, Mission Inn Minnesota, as a defendant.

Bertelson deferred comment to Mission Inn Minnesota attorney Bill Moran, who said the investigation and analysis of the scene are ongoing.

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