RIVERSIDE (CBSLA.com) — A Riverside man says he helped police catch a bank robber and now the bank isn’t paying him the $10,000 reward they advertised.

Brad Lazarus said in 2011 he was in a U.S. Bank branch in Riverside when he witnessed an attempted bank robbery.

READ MORE: Authorities Arrest Suspect Involved In Pursuit Of Suspected Stolen Vehicle, Possible DUI

“I’m not the type to sit on the sidelines,” said Lazarus, who jumped in his truck, chased down the suspect and wrote down his license plate number on the palm of his hand.

He gave it to police, who told him the suspect later robbed another U.S. Bank.

U.S. Bank advertised that they’d pay up to $10,000 for information leading to the conviction of the robber.

Investigators were able to make an arrest with the help of that plate number.

READ MORE: Californians Could Soon Be Fined For Using Too Much Water

The Riverside County District Attorney’s Office confirms the suspect has since been convicted.

Now, after being offered $1,000 in reward money, Lazarus is telling U.S. Bank to “show me the money.”

“I felt it was a slap in the face,” Lazarus said. “I feel that if a big corporation makes an offer that they should stand by it.”

CBS2/KCAL9 asked a bank spokesperson how the dollar amount is determined and were told “Our decision is made in consultation with the police based on the facts of the case.”

MORE NEWS: USC Student Second of Three Confirmed Omicron Cases In LA County

Lazarus said he was planning on sharing the extra reward money with the bank security guard and to give some to charity, but is grateful for whatever he receives.