His wife gave the testimony in an emergency protection hearing in 2012.
The documents say that in 2006, Lam learned through genetic tests that he was not the biological father of his son.
His wife said that Lam physically abused and choked her several times.
Six adults, between ages 25 and 50, and two children under age 10 were found in two separate Edmonton homes Monday night and early Tuesday morning.
Lam was found dead of an apparent suicide in a restaurant in Fort Saskatchewan on Tuesday morning.
Seven of the eight victims have not yet been identified by police. But a boy lived in the home where Lam lived with his wife and their children until recently.
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