Prosecutors have charged a 62-year-old man in the fatal shooting of his 72-year-old mother-in-law at her home in Livingston County's Brighton Township.

Michigan State Police arrested Americo DeCiantis Jr. on Sunday. The Madison Heights man was jailed without bond after his arraignment Monday on charges of open murder, larceny and felony firearm.

The arrest followed more than six weeks of investigation into the death of Louise Marie DeRosia, a widow whose daughter, Linda, is married to DeCiantis.

Authorities say they believe DeRosia was killed Jan. 25. Another of her four daughters, Deborah, found her body the next day after Eastpointe police told relatives that DeRosia's cell phone and wallet had been found outside a White Castle restaurant in the Macomb County community.

Investigators haven't determined a motive in DeRosia's death.