Police took Subhash Chander into custody shortly after the fire erupted. Police say he did not approve of his daughter's marriage. The fire killed Chander's pregnant daughter, her husband and the couple's 3-year-old son.
Prosecutors say Chander confessed to bringing gasoline to the apartment. They say he spilled some during a scuffle with his son-in-law, and then he set the fire in anger.
Chander is charged with three counts of first-degree murder and one count of intentional homicide of an unborn child.
The fire left 70 people homeless.