A Bronx woman was found bludgeoned to death in her apartment on her 30th birthday and cops were questioning her brother, sources said.

Erica Wilson’s mom screamed as she made the grisly discovery around 7 p.m. Thursday in the Brook Avenue apartment in the Tremont section, the sources said.

“I heard screams in the hallway and came out and saw her mom and realized someone had killed her,” a neighbor said.

Her brother was being questioned by investigators at the 42nd Precinct station house but he had not yet been charged with a crime and his name wasn’t immediately released.

The grieving neighbor said she had planned to celebrate Wilson’s birthday with her.

“I was going to take her to get her nails done because today was her birthday,” the neighbor said.

Wilson was pronounced dead at the scene from blunt trauma to her head.