A 59-year-old American woman was found dead of multiple stab wounds inside her home in San Miguel de Allende, a city in the central Mexican state of Guanajuato, the Correo newspaper said on its Web site.

The Guanajuato state Attorney General's Office said agents from its serious crimes unit were investigating the murder of Joyous Heart, the daily reported.

The woman's body was found on the night of Feb. 1 with 40 stab wounds, according to the paper, which added that the woman's adoptive daughter - with whom Heart frequently argued, according to neighbors - is missing.

Correo said the woman was the owner of the house and was renting out rooms to two other foreigners. Those renters told the daily there had been a heated altercation between Heart and her daughter and that they did not see her leave the home afterward, adding that that was unusual.

The daughter was not found at the home and thus far investigators have only learned that she was adopted four years ago at the age of 14 and has been diagnosed with severe schizophrenia, the daily reported.

Correo said Heart's jugular vein had been slashed by a sharp weapon. EFE