Caboolture mother pleads for help after police confirm her child was murdered

A Queensland mother has spoken to 7News saying she wants answers and justice for her young child, who was found dead at a home north of Brisbane last month.

Police say the toddler, Mason Lee, suffered horrific injuries from head to toe and officers are now treating his death as a murder investigation.

"It hurts so bad, that I just, I can't understand it," his mother Anne-Maree Lee told 7News.

"He was just so beautiful he was, so gentle."

Officers from the Child Trauma Task Force and the Homicide Investigation Unit have joined the investigation into the death of 21-month-old Mason Lee.

His body was found at a Caboolture house at about 12.30am on June 11 and investigators believe he may have been dead for some hours before triple-zero calls were made.

Mason's mother has described him as beautiful and gentle. Source: 7News

Police believe that the child's death was unlikely the result of an accident and his injuries were deliberately inflicted, following a post-mortem examination.

"Due to the suspicious nature of the child's death, the Moreton District CIB set up a crime scene that evening and today we can announce the results from the post-mortem examination," Detective Acting Inspector Ben Fadian said.

"He suffered extensive injuries, they were horrific and they were visible from head to toe," said Detective Acting Inspector Ben Fadian.

"While we are awaiting the pathology results, we can say Mason may have been sick or injured for up to a week before he died."

Act Insp Fadian said Mason's injuries appeared to have been inflicted over a sustained period of time.

He said the toddler would have experienced lethargy, vomiting and general unwellness prior to his death and urged anyone with information to come forward.

Mason was found dead last month. Source: 7News

"We're trying piece together not only what happened on that night but also in the months leading up to Mason's death," he said.

"We need to know if he was harmed, sick or injured any time this year."

Act Insp Fadian said investigators had interviewed up to 40 witnesses as part of their homicide investigation but were keeping an open mind.

Anyone with information is urged to contact Crime Stoppers.