LAWRENCE – Prosecutors were expected to present several more witnesses this week in the murder and arson trial of Lynn grandmother Kathleen Hilton.Hilton, 62, stands charged in Lawrence Superior Court with setting fire to a Lynn triple decker on Feb. 24, 1999, that left five people dead.The trial began earlier this month with opening statements before Judge Howard Whitehead, followed by a jury viewing of the fire scene at 44-46 High Rock St. in Lynn. Essex Assistant District Attorney Marcia Slingerland has alleged Hilton torched the building because it was home to her son’s ex-girlfriend, Krystina Sutherland.Hilton was then living nearby at 112 Hollingsworth St. She has been in state prison for the past 10 years.According to Slingerland, the defendant was angry that Sutherland would not let her son, Charles Loayza of Lynn, visit with the estranged couple’s two children and figured she could reunite them if Sutherland were left homeless. Sutherland, who lived on the second floor, escaped unharmed. The fire killed third-floor tenant Heriberto Feliciano, 34; his wife, Sonia Hernandez, 32; their daughters, Sonia, 12, and Maria, 13, and their niece, Glorimar Santiago.Defense lawyer Michael Natola rebutted Slingerland’s assertions at the start of the trial. He has summoned several witnesses who will take the stand once the prosecution rests its case. According to Natola, the fire could have been set by Hilton’s son, Charles Loayza of Lynn. Hilton had no reason to kill her grandchildren, Natola said.Government witnesses who testified last week described fleeing the fire, which quickly flashed through the aging apartment house.Steve O’Connell, spokesman for Essex County District Attorney Jonathan Blodgett, said Monday that additional prosecution witnesses will likely be called to testify throughout the week and perhaps into the early portion of next week.Overall, more than 105 potential witnesses were notified and about 50 will likely be called to testify, according to Natola.