A young woman has died after a fire Sunday in a Longueuil apartment building.

The fire broke out around 9:45 p.m. in the second storey of the building, which was comprised of 8 units, on Marmier St.

An 18-year-old woman, who did not live in the building, went into cardiac arrest and was being worked on by paramedics as she was brought to hospital Sunday night. She died Monday in hospital.

At the time, firefighters suspected the fire started in a mattress located next to a heating element. Longueuil police have taken over the investigation and as of Tuesday evening, they have no theories as to how the fire began.

Damage was limited to the unit where the fire broke out, according to Longueuil police.

Ten other occupants of the building had to evacuate their homes Sunday until the fire was brought under control.