A man jumped in front of a train in Brooklyn Saturday, killing himself after his ex-girlfriend refused to take him back, sources said.

The man, who was not immediately identified, leaped in front of an oncoming L train inside the tunnel near the Halsey St. station in Bushwick shortly after 8 p.m., authorities said.

He died at the scene.

Sources said the man assaulted his ex-girlfriend inside her apartment after she rejected his pleas to take him back.

She was not injured.

After he left, the man went to the subway station and dropped to the tracks from the platform.

He walked down the tunnel before he jumped in front of the oncoming train.