Updated: 08/19/2014 10:08 PM
Created: 08/18/2014 1:18 PM KSTP.com
By: Megan Matthews
The fire that damaged a historic house on one of Duluth's busiest streets has been ruled arson.
Damage to the red sandstone Traphagen House is estimated at over $150,000. It was built in the 1890s and is on the National Register of Historic Places.
No one was inside the three-story building when the fire broke out about 1 a.m. Monday. Firefighters got it under control quickly.
The mansion currently houses HTK Marketing and Communications.
The designer of the house, Oliver Traphagen, also had a hand in other distinctive buildings in Duluth, including the former City Hall and Fitger's Brewery.
Fire officials say it's not clear if there's a connection with another incident in which a bottle with an accelerant was thrown through the window of a building across Superior Street.
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