The police have collected data from the mobile phone of Abdul Rahman Adam's wife.
The 65-year-old man was brutally murdered in his home in Alif Alif Maalhos on July 13.
His wife Nazima Ibrahim's phone was seized on Thursday and returned later in the night.
"They said they wanted to collect data from the night my father died," said the couple's son Ahmed Nimal.
Police did not say why they seized Nazima's phone.
In a statement, police said they were talking to people close to Abdul Rahman's family and trying to find out the truth with their cooperation.
"We are conducting separate efforts focusing on various angles in the investigation," police stated.
Police have not been able to determine Abdul Rahman's killer and the exact motive behind the brutal killing.
His body will be taken to India for a post-mortem on July 21. A police forensic and homicide department team went to the island on July 13 to investigate the case.
