An arrest has been made in connection to the alleged murder of heavily pregnant aged care nurse Janet Dweh, five days after her body was found at her Perth home.

Police have yet to formally release details, but have confirmed an arrest has been made.

Ms Dweh was due to give birth to her fourth child just weeks before her bloodied body was found at her house in Dayton, a quiet suburb in Perth.

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Yesterday, the homicide detectives announced they were closing in on Ms Dweh's alleged murderer, with authorities believe she was killed sometime between Sunday evening and Monday morning.

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The person suspected of the killing is believed to be well known to Ms Dweh, having either used a key to enter Ms Dweh's property, or were invited in.

Eight months pregnant, the 36-year-old was just weeks away from giving birth to her fourth child.

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Her body was discovered by her brother at her home on Mataro Drive, near Garrido Way, in Dayton at around 6pm.

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Friends said Ms Dweh was a refugee who had fled war-torn Liberia in search of a better life.

She worked in Perth as an aged care nurse and had already started her maternity leave.