Speaking exclusively to News 12 Long Island, Nassau?s police commissioner discussed for the first time the investigation into how officers handled threats made against a New Cassel mom who was later killed.

Joanna Bird?s family says their loved one would be alive if cops had arrested her accused killer sooner. Bird was found stabbed to death in her home on March 19 and the next day her ex-boyfriend Leonardo Valdez-Cruz was arrested and charged with her murder. The family claims Valdez-Cruz was harassing Bird at her mother's house the day before she was killed and that he should have been arrested for violating an order of protection. Instead, they say, cops let him go.

Police Commissioner Lawrence Mulvey finally talked about the case. He confirmed that police were called to Bird's mother's house on two different occasions in the days leading up to the murder.

?We're attempting to determine the nature of those calls, which officers responded, and what were the circumstances that occurred during those contacts,? Mulvey says.

Mulvey says the police department's internal affairs unit is investigating the way police handled the two calls. He would not talk in any detail about the investigation, except to say that it will be thorough and transparent, and could result in changes to the way the department deals with violations of orders of protection.

Mulvey would not say exactly when he thought the investigation would be completed.