Police said this afternoon that they had identified a suspect in the deaths of Brenda Anderson, 94, and her husband Lynton, 94, with suspicions raised by “similarities and abnormalities” in toxicology results for the pair.

Brenda Anderson was being treated for medical issues in at Noarlunga Hospital in March last year but her condition worsened and she was taken to the Flinders Medical Centre, where she died.

On April 30 this year, Lynton Anderson was found unconscious by a carer at his Hackham home and taken to the Flinders Medical Centre, where he died the next day.

Detective Inspector Mark McEachern said concerns were first raised when Mrs Anderson’s toxicology results were revealed during a coronial investigation.

“When an innocent explanation for toxicology abnormalities was eliminated, the possibility of Mrs Anderson’s death being a deliberate act by another party became the primary subject of the investigation,” McEachern said.

“It is believed Mrs Anderson was killed by a person known to her and in close enough relationship to have been visiting her while she was in hospital.”

He said police had no concerns about the level of care she received in the hospital, and had ruled out anyone there being involved.

Suspicions were also raised by the circumstances of Mr Anderson’s death and his toxicology report.

“Police have eliminated external carers involved with Mr Anderson’s care as being involved in his death,” McEachern said.

“We have identified a suspect and won’t elaborate further.”

Police have appealed for anyone who knew the couple and may know something about their deaths to contact them – “In particular, anyone that may have knowledge of prescribed or non-prescribed medications each were using or had spoken about.”

Anyone with information is asked to call Crime Stoppers on 1800 333 000.