Police have arrested a 50-year-old woman in Tin Shui Wai over the March 4 murder in Sham Shui Po.

About 9.45am on March 7, an 87-year-old woman was found collapsed inside her premises at Mei Choi House, Shek Kip Mei Estate. She was found bound and gagged on the floor and confirmed dead at the scene.

Police believe she had been visited by the suspect three days before her body was found.