NASHUA, N.H. (AP) – Prosecutors say a 20-year-old man charged with killing his grandfather in Nashua, N.H., struck the victim with a hatchet before setting his house on fire.

Michael Phillips is being held without bail on first-degree murder and arson charges in Thursday’s death of 68-year-old Franklin Phillips.

The two lived together in Nashua.

Authorities would not comment on a possible motive.