A retired federal agent's research has uncovered the records which show that the United States first female cop was an Irish woman.

While researching the history of Chicago law enforcement, Rick Barrett, a former Drug Enforcement Administration agent and amateur historian, discovered records of Sergeant Marie Owen, the first female cop in the United States and an Irish-born woman.

Barrett spent over three years researching  Owens. He spend his time travelling all over the city befriending archivist pulling in favors with pension records, civil service documents and cemetery plot listings. Eventually it paid off.

"She wasn't wealthy. She was Irish. She was Catholic…She had all of these strikes against her, and so they just wrote her off," said Barrett.

She was both written off by the police department and therefore out of history. However Owen's story was well covered by the turn-of-the century press. Unfortunately her story got lost in about 1925 when historians confused her story with another woman's tale.

As a result Ms Owen's accomplishments were erased. Barrett believes his findings to be accurate. Dave MacFarlan, a police historian and member of the Chicago Police History Committee says that if he is correct it would be "huge".

Allegedly  Owens started working as a police officer in 1890. Until now historians had believed that the first female officer was hired in 1913.

Russell Lewis, chief historian at the Chicago History Museum agreed. He said "It's a big deal, and it's great for Chicago."