A toddler has succumbed to her injuries in the hospital, bringing the death toll to three family members in a Tuesday night house fire in Richmond that police believe was intentionally set by a 32-year-old man who lived there.

The two-year-old's death was announced early Thursday by Richmond Police Lieutenant Joe England, as KION reports. The sole survivor of the fire is a 33-year-old woman who remains in critical condition.

As SFist reported Wednesday, police arrested a suspect who was at the scene of the fire among some onlookers. He has been identified as 32-year-old Sergio Rivera Vega, who lived at the home where the fire occurred with his father, sister, and his sister's two small children.

The fire broke out Tuesday night, following a fire at a house next door that had begun around 8 pm. Per KTVU, as firefighters got the first house fire at 231 15th Street under control, they noticed another fire underway one door down at 239 15th Street.

As firefighters moved into the second house, they found four unconscious individuals inside, including the two-year-old girl and her five-year-old brother, their 33-year-old mother, and 47-year-old grandfather, Jose Rivera.

The mother and children were all hospitalized with critical injuries, and the grandfather was pronounced dead at the scene. The five-year-old boy was pronounced dead at the hospital Tuesday.

Rivera Vega was soon arrested on suspicion of arson and two counts of murder, and when charges are filed, there will now likely be a third count of murder.

A family member, Anselmo Rivera, identified the suspect as his nephew, and said that he suffers from mental health issues, per KTVU. The sister's name is reportedly Maria, the children's names were Jolene and Andrew, Rivera said.

Rivera Vega is being held in jail in Richmond on $2.5 million bail.

Strangely, the first house fire at 231 15th Street is also being investigated as an arson, and a female suspect was arrested in connection with that. No injuries were reported in that fire.

Previously: Arson Suspect Arrested In Richmond Fire That Killed Father, Nephew