An ex-boyfriend of the Westchester woman whose body was found stuffed in a suitcase along a Connecticut roadside last week has been arrested in connection with the death, cops and reports said Tuesday.

Javier da Silva was nabbed by detectives from both New York and Connecticut after he used an ATM card belonging to the victim, Valerie Reyes, to withdraw cash from her account, according to the Greenwich, Conn., Police Department.

Da Silva — a Venezuelan citizen living in Queens illegally after overstaying a visa, sources told CBS 2 – NY — was busted in the borough Monday night, though Greenwich cops didn’t divulge exactly where or when.

Greenwich police also wouldn’t address da Silva’s immigration status, though the federal Immigration and Customs Enforcement said that they were looking into it.

“Now that we are aware of him, we will take steps needed to confirm his alienage and issue a detainer as needed,” an ICE official said.

Under questioning by New Rochelle and Greenwich detectives, da Silva “admitted a role in the death of Valerie Reyes,” said Greenwich Police Capt. Robert Berry in a Tuesday afternoon press briefing, though he declined to elaborate on that role.

The body of Reyes, a 24-year-old New Rochelle resident, was found on the morning of Feb. 5 just off Glenville Road in Greenwich, about a mile from the Merritt Parkway.

News of the arrest came on the day Reyes was mourned by weeping family and friends at a packed New Rochelle wake.

Da Silva is expected to appear in White Plains federal court Tuesday afternoon because Reyes’ death and the dumping of her body crossed state lines.

The precise charges are pending.

Greenwich police credited the arrest to an extensive, multi-agency investigation.

“This entire investigation has been a herculean effort from the very beginning, from the initial officers on scene to all the work of all the detectives chasing down numerous leads,” said Berry.

“Multiple crime scenes had been examined, hundreds of hours of surveillance footage had been reviewed, and numerous interviews of potential witnesses had been conducted,” the department wrote on Twitter. “Additionally, social media footprints and records from a variety of sources have been analyzed.”

“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.”

Additional reporting by Alex Taylor