By CBSLA Staff

LOS ANGELES (CBSLA) A woman pleaded not guilty Thursday to murdering an off-duty Metro employee at a downtown Los Angeles rail station last year.

Irma Beatriz Monroy, 25, of Los Angeles, allegedly got into an argument with Louis Rabinowitz, 54, inside the Metro B Line train near the 7th Street/Metro Center Station and stabbed him once in the chest on Oct. 16.

READ MORE: 1 Killed, 1 In Critical Condition After Shooting Near Eagle Rock Dispensary; Suspect In Custody

Investigators said the Monroy was seen exiting the station pushing a “distinctive” green bicycle.

Monroy was arrested three days later by police officers with the Los Angeles Police Department.

Officers recovered the alleged murder weapon, a knife, along with the bicycle, police said.

READ MORE: Southland Scholars, Pastors And Activists React To Juneteeth, Nation's First New Federal Holiday Since Martin Luther King Junior Day

Metro CEO Phillip A. Washington said Rabinowitz had worked at Metro for more than 18 years, most recently in the rail operations division.

“It is through this quick response that riders and fellow Metro employees can be assured that safety on our system is top priority and individuals who commit such acts of violence will be aggressively pursued and brought to justice,” Washington said.

Monroy has remained in jail since her arrest. She had been charged in a separate case last Sept. 25 with one count of assault with a deadly weapon for allegedly assaulting her brother with a weight on Aug. 31.

MORE NEWS: Cal/OSHA Votes To Let Vaccinated Employees Shed Face Masks In The Workplace

(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)