DALLAS -- Investigators went back to the scene of a deadly fire this weekend that claimed lives of two children.
Investigators sifted through the charred rubble of an upstairs unit at the Casa Flores Apartments in southeast Dallas. An official cause of the fire has not been released.
Yenfry Jimenez lost two of his four children in an apartment fire Sunday morning.
'It hurts me that I couldn't be there to help them,' he said. 'I tried to help them.'
Jimenez tells News 8 his estranged wife and their five-month-old are both in an intensive care unit, and are expected to recover.
Franklin Pratt watched from below as investigators did their work Monday in the 2600 block of Highland Road.
'It wasn't a good day yesterday,' Pratt said. 'We did the best we could. We hung in there as long as we could.'
He was among the residents who tried to save two children trapped in the burning apartment Sunday morning. Pratt said they went through several fire extinguishers, but they weren't strong enough to douse the massive fire.
'Mostly it was little kids running around [and] getting the fire extinguishers; bringing them to us so we could use them,' Pratt said.
Five-year-old Nathaniel Jimenez and his three-year-old sister, Natalie, died. Their mother suffered burns over 30 percent of her body.
'When I sleep, I hear them in my mind calling me, and I am picturing my son calling me for help,' Jimenez said.
He has opened an account at First National Bank to raise money his family's recovery.
The cause of the fire is still under investigation. Jason Allen, a spokesperson for the Dallas Fire Department, said it will likely take several days to complete a report on the fire.