Mr Schinkel, 31, was taken to hospital with serious injuries after being found unresponsive at central Queensland's Capricornia Correctional Centre in October 2022.
He died the next day.
Mr Schinkel had been in the prison near Rockhampton for barely a month.
He was eligible for parole in January.
Police said Mr Schinkel's injuries indicated they were the result of a serious assault.
Detectives have set up Operation Uniform Carlow to investigate his death, which is being treated as a homicide.
Police and Mr Schinkel's family want to hear from anyone with information about his death.
Mr Schinkel's father said his son was missed by many, describing him as a loving, caring person who would do anything for his mates and family.
"We really are appealing to anybody out there if they could come forward to help us solve Benn's murder," Michael Schinkel said.
"It's broken our family and we need to have justice."
Benn Shinkel died from injuries consistent with a serious assault.
Mr Schinkel was jailed for a December 2021 dangerous driving incident, which left him with ongoing injuries and a limp. His ute crossed onto the wrong side of a highway and smashed head-on into a semi-trailer. No one else was injured.
Detectives said a number of people had been interviewed across the state about Mr Schinkel's death.
It is believed there are people living in the Townsville and Rockhampton areas who may be able to assist their investigation.
"Everyone in custody has the right to do their time, to go home to their families and move on with their lives," Detective Sergeant Greg Bishop said.
"We urge anyone with information regarding this incident, no matter how small or insignificant it may seem and whether you witnessed the incident directly or have heard something from another person, to please come forward."
Reports to Crime Stoppers - 1800 333 000 - can be made anonymously.
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