Police were called to a two-storey shophouse behind Prakanong Market at 6.30am to find the body of three-year-old Areeya Saelee on the second floor of the building.

Her 31-year-old mother, Benjawan Saelee, had been rushed to Kluaynamthai 1 Hospital.

A suicide note was found in which Benjawan said a suspicious and painful lump had developed under her arm so she had decided to take her own life and her daughter's.

Benjawan's sister, Supak Saelee, 28, who lives in a nearby condominium told police that after her sister's marriage failed she had raised Areeya on her own. Supak helped fund a cosmetics shop for her to work in.

She said Benjawan called her at 5am and said she was dying. Supak rushed to her house and found Areeya dead and Benjawan in agony from having drunk disinfectant, so she took her sister to hospital.

Police suspect that Benjawan - stressed from a discovering the lump under her arm - had mixed disinfectant with Areeya's milk on Monday night and then laid beside the body of her daughter until early yesterday morning when she attempted to commit suicide.

However, her sister managed to get her to hospital in time.

Benjawan, who was said to be in grief and very distressed,

was under the close watch of

four relatives but was not yet ready to face questioning by the police.