SAN DIEGO (NEWS 8/CNS) - Grief counselors met with students and parents at Sunset Hills Elementary School Monday, as students and staff mourn the deaths of two siblings.

The brother and sister who were pulled from a fire in a second-floor apartment in the Rancho Bernardo community were killed. That fire is still under investigation, police said Monday.

A 37-year-old father and his two children were found unconscious when firefighters arrived after a fire broke out in the 11000 block of Bernardo Terrace.  

It took about 20 minutes for firefighters to knock down the blaze. 

San Diego Police Lt. Mike Holden confirmed the two children, a 7-year-old girl and a 10-year-old boy, died after the fire. 

Sam Trink, like many Sunset Hills Elementary School parents, couldn't believe two of her son's friends from school were killed in an overnight fire. 

"It is horrible. Two kids one day," said Trink. "They were just great kids, very well liked. My son is best friends with their son. 

"They've known each other since kindergarten. The younger sister is kind of like a younger sister to my son. They were at the Halloween carnival last night. Everyone saw them last night."  

Firefighters say the fire started around 3 a.m. in an upstairs condo.  When they arrived they found 7-year-old Isabella and her 10-year-old brother Cristos unresponsive.   

Both children were pronounced dead at area hospitals.  Their father Henry Lopez was hospitalized and as of Sunday evening he remained in serious condition.   

The parents were reportedly in the middle of a divorce and the children stay with their father on weekends.  Their mother lived elsewhere and got the news soon after.  

"Bella was like a little princess," said Trink. "She loved playing with her mom's make up and wanted to be like her older sisters. She wanted to be a doctor she wanted to help people."  

Arson and homicide investigators wrapped up their investigation on-scene late saturday night.

So far they haven't released a cause, but stressed it might be accidental.

Meanwhile the Poway School District is working to help parents explain what happened to their classmates

The principal of Sunset Hills sent the following letter to families: 

Dear Sunset Hills Families, 

It is with great sadness that we share with you that two Sunset Hills students lost their lives in an overnight fire. 

Our hearts go out to the family and friends of these students, who were in 2nd and 5th grade. They will be remembered for their warm hearts and happy spirits, and leave behind many positive memories. 

We will have counselors on campus to support any students and staff who have been affected by this loss. In the meantime, if you need ways to help your child during this difficult time, please visit our website for some strategies. 

We will be reaching out to the family about how our community might support them. 

Your Principal, 
Lisa Wilken 

A Go Fund Me campaign has been established to help the family with funeral costs.