An investigation is underway after a double drowning Thursday night in a Granger neighborhood.

Police say a grandfather,55 year old David Prentkowski and his 18 month old granddaughter Charlotte Chelminiac are dead after they were found at the bottom of a pool in Granger.

The coroner ruled the preliminary cause of the child's death as accidental drowning.

An autopsy on Prentkowski will be conducted this afternoon.

David Prentkowski was the Director of Food Services at the University of Notre Dame. He had been undergoing treatment for pancreatic cancer and was honored at this year's Relay for Life at Notre Dame.

The grandparents were watching their granddaughter while their daughter was away at work.

It happened at about 7:30 p.m. at the 52000 block of Glen Arbor Ct.. That's in the Brendon Hills subdivision near the intersection of Brick and Gumwood Road.

St. Joseph County Police say the 55-year old was dead at the scene. The 18-month-old was given CPR but died a short time later at the hospital.

Officers at the scene were told that the man had taken the 18 month old for a walk while his wife prepared dinner. When they did not return, the wife sent her son to look for them.

The son returned from checking the neighborhood and found the man and child on the bottom of the pool. The son and his friend then jumped in and pulled both victims from the pool.

Police don't know exactly what happened but believe the grandfather jumped in the pool to try and save his granddaughter.

The names of the victims are being withheld at this time pending notification of family.