ST. CLOUD — A St. Cloud teenager has pleaded guilty for his role in an accidental house fire that killed his grandmother.

A jury trial for 19-year-old Dustin Zablocki was supposed to begin Tuesday. But Zablocki pleaded guilty last week to aiding and abetting third-degree murder in the death of 85-year-old Sally Douglas in late 2014.

Zablocki agreed to a seven-year sentence, with credit for time served. The last third of his sentence will be served on supervised release.

Another suspect, 20-year-old Justin Pick of Sartell, pleaded guilty earlier to the same charge.

Investigators say the fire started when Zablocki and Pick were making an extract from marijuana known as “dabs” or butane hash oil.

Zablocki’s attorney, Kenneth Wilson, says his client thought his grandmother wasn’t home.