New $1 million rewards have been announced in a bid to crack open two South Australian baby death cold cases.
Police have renewed their call for information into the unrelated deaths of Lily Jean Schettini in 2010 and Dylan Robert James Lindsay in March 2004.
Dylan was found dead at a Ellen Street, Port Lincoln property with visible abdominal injuries after a serious assault.
His mother, who was struggling with substance abuse, had left him and his older sister in the care of friends and there also three other children in the house at the time.
Someone attempted to disguise Dylan's injuries by using a texta to cover the bruising and marks, police say.
Two people were arrested in May 2004 in connection with Dylan's death, but the case was later dropped as there was no reasonable prospect of conviction based on the evidence at the time.
"This is a heinous crime and somebody should be held responsible for taking the life of this child in a severe assault," Detective Brevet Sergeant Mathew Bengel, from Major Crime, said in a statement.
"We did a lot of work with the texta pens we found in the house - fingerprints and DNA testing and so forth.
"We certainly believe we have identified the texta used, but we're unable to determine who drew on him."
Lily was found unresponsive in a Smithfield Plains home in 2010 and died from blunt force trauma consistent with being shaken, assaulted of falling, police say.
Police believe she was injured by one of four adults in the house at the time.
"Lily lived at the home with her sister, her mother and her mother's defacto partner, but that night there were also two visitors - a man and a woman - at the address," Detective Senior Sergeant Mark McEachern, from Major Crime, said in a statement.
"This family was not known to the authorities, however police have concerns about the care of the children in the lead up to this death."
Anyone with information about either of these cases is asked to call Crime Stoppers on 1800 333 000 or report online at https://crimestopperssa.com.au/