WYANDANCH, N.Y. — A Long Island man was in police custody after his wheelchair-bound mother and stepbrother were fatally stabbed in what appeared to be a domestic dispute.

His stepfather also suffered serious wounds in the Monday attack.

Suffolk County Police arrested 30-year-old Courtney Williams just blocks from his Wyandanch home a short time later. Police say he’ll be arraigned Tuesday on murder and attempted murder charges. The name of his lawyer was not immediately known.

Earlier, officers found Williams’s wheelchair-bound mother, 52-year-old Queen Mobley, and stepbrother, Ernest Mobley Jr., suffering from stab wounds inside their Jackson Street home. They were taken to a hospital, where they were pronounced dead.

Ernest Mobley Sr. was also hospitalized, but is expected to survive.