The Rensselaer County Sheriff's Office say the people are known to investigators looking into the blazes set in neighboring Schaghticoke and Pittstown.
The latest arson fire was set in a garage in the village of Schaghticoke around 3 a.m. Thursday. Officials say the flames jumped to a neighboring house where a family was sleeping. No one was injured.
Investigators say the fires have tended to be set in the early morning hours in buildings that have been abandoned or were empty, including an old mill in the hamlet of Valley Falls that was torched in April 2009.
No arrests have been made.
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