Trivia: Just after the scene when Waingro escapes being killed, there's a shot of De Niro looking at the sea through the glass with his left arm touching a window frame, and his automatic gun on a little table. This shot is inspired by the picture "Pacific" (1967) made by the Canadian artist Alex Colville.
Trivia: Despite receiving top billing, Al Pacino and Robert De Niro hardly appear on-screen together. The two actors spend less than ten minutes of the entire film in one another's presence.
Trivia: According to the DVD extras, a new couple have moved into the house where Trejo and his wife Anna were killed. The lady of the house pulled back a carpet and points with pride where one can see the fake bloodstains of Trejo as he lay dying in the room where McCauley found him.
Trivia: In the original cut, during the armored car investigation Bosco is getting eyewitnesses testimony and someone saw a tattoo of a bird or something. This is why Hanna knows its him when he's talking to Richard Torena later. The peacock. They edited that dialogue out for the DVD because they realised all arms were covered during the robbery, so the witness couldn't have seen the tattoo.
Answer: Waingro helped Van Zandt track down Trejo. Waingro then tortured Trejo and threatened his family if he didn't give up McCauley. With his back to the wall, Trejo gave Waingro and Hugh Benny the details of the bank heist, but Waingro killed Trejo's family anyway and beat Trejo almost to death. Benny then gives the tip to the police on Van Zandt's order.
BaconIsMyBFF
I wonder how Trejo was tracked, I don't remember his name being revealed during Waingro's time with the crew, or any other information.
Well, we never see the crew prior to their first heist. Trejo could have given Waingro his name during the planning of that heist.
BaconIsMyBFF
Waingro met this crew only once. How would he know who Trejo is or where he lives? Right before the heist, Trejo is asked to mislead police away from the heist.