Results of tests to establish how a Scottish aid worker died in Greece could take another month, the BBC has learned.

The body of Elisabeth Ross, who was 38 and from Edinburgh, was discovered in a suitcase by a homeless man in a derelict building in the Kypseli area of Athens on 18 July.

Sharif Ahmadzai, 26, a boxer from Afghanistan, has been accused of her murder as well as robbery and weapons offences.

Greek police previously said they were fast-tracking tests as a priority.

But on Saturday, spokesperson Konstantina Dimoglidou told BBC Scotland News the test results could take “at least another month”.

Ahmadzai was initially detained on illegal weapons possession charges and is facing a charge of homicide with intent, as well as allegations that he stole more than €10,000 (£8,500) from the victim’s bank accounts using her bank cards.

The police union in Greece said that initially, the coroner’s report cited an undetermined cause of death, as the body showed no signs of external trauma.

It said following a more detailed investigation, autopsy and post-mortem examination, “asphyxiation was listed as the probable cause of death”.

In a statement released on Thursday Ahmadzai’s lawyer said that when Ross was found, she had no injuries and any apparent cause of death was “entirely absent”.

He said his client wanted the forensic medical report and the “toxicological and histological examinations of the deceased” to be included in the case file.

Ahmadzai was remanded in custody until his trial, which could take up to 18 months.

The BBC has been told Ahmadzai denies homicide with intent but admits moving the body, claiming that he did so because he feared he would be blamed for her death.

A statement from the organised crime directorate said Ahmadzai was brought to a police station on 30 July.

Ahmadzai is accused of killing Ross, then sending a series of messages from her phone to her friends and family before switching off the device.

Greek newspapers reported his wife told the police she suspected her husband’s involvement in the killing when she woke up to find he was not in their apartment and tracked his phone to where Ross was staying.

The statement given to police by Ahmadzai’s American wife has been described as crucial to the investiagtion.

Police said Ross – who is known to family and friends as Lisa – had been volunteering with a refugee support group based in Athens.

She arrived in Greece on 26 June and stayed in the Keratsini area of Piraeus until 10 July.

Ross is believed to have died a number of days before she was found.

Greek officials contacted Interpol and American authorities were able to identify her fingerprints.

Her family described her as “kind, principled and selfless”.

“Her integrity was absolute, and she dedicated her life to helping others in need,” a statement said.