Two-year-old boy allegedly killed by guardians who took him in after his father murdered his mother

Joshua Rukovishnikoff was taken in by Steven Melovidov and Sophie Myers-Melovidov after his father allegedly strangled his mother

The boy was killed on St Paul Island in Alaska (AP)

A two-year-old boy has allegedly been murdered by his guardians just two months after they took him into their home on a remote Alaskan island, when the child’s father allegedly strangled his mother to death.

Joshua Rukovishnikoff was repeatedly struck on the head by Steven Melovidov, 31, and Sophie Myers-Melovidov, 28, at their home on St Paul Island back on 11 December, according to an affidavit seen by Anchorage Daily News.

The boy was rushed to a hospital on Anchorage where he succumbed to his injuries while the couple sought to mislead investigators, texting each other to try to cover their tracks, authorities said.

An autopsy revealed the toddler had suffered at least five separate head injuries and had multiple suspicious bruises on his genitals.

Mr Melovidov and Ms Myers-Melovidov were arrested and charged with  first-degree and second-degree murder and fourth-degree assault.

Joshua was taken into the care of the couple now accused of his murder back in October, following the tragic death of his mother Nadesda Rukovishnikoff.

Authorities said Ms Rukovishnikoff was strangled by her husband Joshua Rukovishnikoff during a violent domestic incident in September.

Mr Rukovishnikoff was arrested and charged with his wife’s murder. He has pleaded not guilty.

On 11 December, less than two months after Joshua began living with the Melovidovs, police said they received a 911 call about a toddler having seizures.

The boy was rushed to hospital and found to have a serious head injury. He died the following day.

The Melovidovs initially told investigators that the child had fallen at home.

But the couple’s version of events quickly unraveled following further investigation, authorities said.

According to the affidavit, the autopsy found his injuries were consistent with homicide.

The couple also allegedly exchanged text messages when the boy was in hospital, discussing hitting him in his head and being concerned that medics would discover the injuries when he went for a brain scan.

“Gees and we’ve been hitting his head,” Ms Myers-Melovidov allegedly texted her partner, before urging him to delete their messages.

“Please delete our texts now.”

Investigators said the couple also told their eight-year-old daughter to lie to authorities about what she witnessed in the home.

The affidavit said the couple had “repeatedly stuck Joshua in the head, which resulted in a brain bleed and ultimately resulted in Joshua’s death”.

“Additionally, there were multiple suspicious bruises on Joshua’s genitals that were not consistent with medical treatment,” it read.

The couple pleaded not guilty to all charges at a court hearing on Thursday.

They are being held on $250,000 bond each and have been ordered not to have any contact with their daughter.