The genuine winning ticket, which was bought in Worcester, has never been found.
He said he killed the children because one of them would not stop crying.
A three-year-old boy was left with serious burns to his face and arm.
Thomas Jones, 18, was missing for nine days before his body was found in the River Severn.
The 20-year-old leapt from the dock and ran past astonished staff.
There will be no further details until formal identification takes place.
18-year-old Thomas Jones had just started a teaching course at the University of Worcester.
Five others have already appeared in court, including victim's father.