The ex-boyfriend of the New York woman whose body was found inside a suitcase in a wooded area of Connecticut was held without bail on Tuesday on a charge carrying a potential death penalty.

Javier Enrique Da Silva Rojas, 24, of Queens, New York, was detained in the death of 24-year-old Valerie Reyes after he appeared in federal court in White Plains, New York.

The victim's body was found on Febuary 5 inside a suitcase discarded near a Connecticut road by highway workers. The discovery came after she was reported missing on January 30 by her mother, father and boyfriend, authorities said.

Da Silva Rojas was arrested in Queens, New York, on Monday. A defence lawyer did not immediately return a message seeking comment.

Federal authorities said Da Silva Rojas told authorities in a videotaped interview at the New Rochelle Police Department that Reyes fell to the floor and hit her head after they had sex on January 29 at her residence.

They said he indicated he put packing tape over her mouth, bound her legs and hands, and put her in a suitcase that he put in a forest after driving for some time.

Da Silva Rojas was charged with kidnapping resulting in death, which carries a potential penalty of death or life in prison. Prosecutors have not yet indicated if they will seek death if he is convicted.

William F Sweeney Jr, head of the FBI's New York office, said federal authorities teamed with police in Greenwich and New Rochelle to "swiftly identify Javier Da Silva, an alleged murderer, and place him behind bars".

"While today's arrest is certainly a welcome conclusion, it in no way alleviates the pain and suffering Valerie's family will continue to feel for years to come. The reality of their situation is utterly unimaginable, as is the crime with which Da Silva is charged," Sweeney said.

Investigators "zeroed in" on Da Silva Rojas after he allegedly used Reyes' ATM card to withdraw cash multiple times after her death, Greenwich Police Captain Robert Berry said.

"We are confident that the pursuit of justice for Valerie will be successful and we continue to work with the family to provide closure to this tragedy," Berry said in a written statement.

Reyes, of New Rochelle, New York, was reported missing when she did not show up for work January 30 at a bookstore. Autopsy results from the Connecticut Office of the Chief Medical Examiner are still pending.

Police said they have examined hundreds of hours of surveillance footage in the case and interviewed several potential witnesses.

Reyes had worked at a Barnes & Noble store in Eastchester, New York, since it opened 2 ½ years ago, according to the bookstore chain.