A Lithuanian charged with the murders of an Indian-origin man and his British wife at their home in Birmingham has committed suicide in police custody, a media report said.

Avtar Kolar, 62, and Carole Kolar, 58, were beaten to death with a hammer in Handsworth Wood area of Birmingham in the earlier part of January, Sky News reported.

Rimvydas Liorancas, 37, who was arrested Jan 16, was found hanging in his cell at Woodhill prison in Milton Keynes Saturday, officials said.

Prison staff attempted resuscitation but he was later pronounced dead.

Police said said investigation into the couple's murder would continue and the findings handed to the coroner.

"The family of Carole and Avtar were informed at the earliest possible stage of the news and we are continuing to support them," police said in a statement.

One of the Kolars' sons is a serving police officer but officials said their deaths were not related to his job or investigations into gangs.

The bodies of the couple, married for 40 years, were found at their property by their son. Postmortem examinations revealed that both died as a result of blunt force trauma to the head, each sustaining a number of blows, the Guardian said.