The 33-year-old woman who was critically injured in a house fire allegedly set by her brother on Tuesday has died, the police department said on Saturday. Police said Sergio Rivera-Vega was accused of starting the fire at a home located along the 200 block of 15th Street on Tuesday night. The bla ze killed Rivera-Vega’s 47-year-old father and his 5-year-old nephew, his 2-year-old niece and now his 33-year-old sister. Rivera-Vega lived in the home. Police said a motive for the alleged arson is still under investigation. “Our investigators, their number one goal is to figure out why this happened, why this person would do this to their family,” England said. “That is what everybody wants to know.” Richmond Aug 20 2-year-old girl dies after suspected Richmond arson, bringing death toll to 3 Richmond Aug 19 Arrest made in suspected Richmond arson that killed man, 5-year-old boy The day of the incident, firefighters had responded to a fire nearby at about 8:15 p.m. After that fire was under control at about 8:45 p.m., bystanders alerted them of another fire at a nearby home, which is the one Rivera-Vega allegedly started, according to authorities. The second fire was under control by about 9:25 p.m., according to officials. Three of the victims were taken to the hospital, where they died. The suspect’s father died at the scene. Police said all of the victims were injured or killed by the fire, and there is no evidence that they were shot or stabbed before the alleged arson. ...read more read less