New Delhi:  Left by a teenage girl at the All India Institute of Medical Sciences (AIIMS) here, battered two-year-old Falak on Tuesday continued her fight for survival even as Delhi Police continued their search for the key accused in the case.

Falak is now being administered a range of antibiotics for chest and brain infection, doctors said.

"Baby Falak continues to be in a critical condition. There is no material change in her condition. Infection is a cause for concern," M.C. Misra, chief of the All India Institute of Medical Sciences (AIIMS) trauma centre, said.

The next two days are crucial for the baby who is currently on a ventilator. The culture report of the brain fluids and response to antibiotics will help doctors ascertain if Falak has to undergo another surgery, doctors said.

"Once we get culture report (of the fluids in the brain), the next 72 hours to 5 days (to Sunday) are very crucial for this child," Misra added.

The baby underwent a second brain surgery on Monday.

Falak was admitted to AIIMS here January 18 with multiple injuries, including a fractured skull, human bite marks on her tiny frame and a clot on the right side of her brain. She was brought to the hospital by a teenaged girl who claimed to be her mother.

The teenager is now in a juvenile home.

Meanwhile, police carried on their search for missing links in the case and said it is close to cracking the case. A police official listed arrest of key accused Rajkumar Gupta as the main priority.

"First we are working towards catching Rajkumar as soon as possible and second we are trying to find the parentage of the baby," Deputy Commissioner of Police (south) Chhaya Sharma told reporters here.

A police team is in Mumbai but is yet to locate Gupta who got the baby from Laxmi, a resident of Uttam Nagar in west Delhi.

Laxmi in turn got the baby from her biological mother, Munni. Gupta had left the baby with his minor girlfriend before heading to Mumbai for the treatment of his son.

Survival chances for Falak are slim, say doctors, who said they are hoping for miracles. The baby shows faint flicker of hope as she opens her eyes and blinks."We will monitor her lung condition as there was slight improvement in neurological condition on Tuesday.

Infection is the main concern because she suffers from meningitis that infects fluid in brain," said Sumit Sinha, associate professor of neurosurgery at AIIMS."If she does not respond to the antibiotics within 24 to 48 hours, we have to see what is to be done," Sinha added.