Authorities say they arrested in Puerto Rico the Waterbury man accused in the double fatal shooting of a 20-year-old Massachusetts woman and her infant son.

Lance Benuet Morales, 23, is police custody and awaiting extradition to Connecticut.

Members of the U.S. Marshals Violent Fugitive Task Force say they found Morales in the town of Fajardo, Puerto Rico on Saturday.

Morales is alleged to have shot and killed Jessiah Mercado and her 4-month-old son, Messiah Diaz, and injured a third person.

Hartford Police say Morales's car pulled up alongside the victim's car and started to shoot on New Britain Avenue in Hartford Tuesday afternoon.

The injuries of the third person who was shot were not life-threatening.

MORE: Police: Suspect's vehicle recovered following double fatal Hartford shooting

“Since the commission of this senseless and heinous act of violence, investigators from the Hartford Police Department and the U.S. Marshals Service Violent Fugitive Task Forces in Connecticut and Puerto Rico have tirelessly worked around the clock to bring the suspect to justice,” said acting U.S. Marshal for the District of Connecticut, Lawrence Bobnick. “This arrest is a testament to the close collaboration between the U.S. Marshals Service and our valued law enforcement partners and it demonstrates the reach these partnerships bring to the pursuit of justice.”

Morales is being held on a $3 million bond.

He faces charges of criminal possession of a firearm, assault in the first degree, criminal attempt to commit assault in the first degree, two counts of murder, and murder with special circumstances.