An undocumented migrant accused of killing his New York girlfriend on her 21st birthday allegedly strangled her to death then dumped her body in a shallow grave.

Jhon Moises Chacaguasay-Ilbis, 21, has been charged with second-degree murder and concealment of a human corpse in connection with the death of Joselyn Jhoana Toaquiza, according to prosecutors, The Post-Standard, WSTM-TV, and WSYR-TV reported.

He pleaded not guilty to the charges.

The couple met in elementary school in Ecuador and were celebrating her milestone birthday when she was allegedly killed June 18, prosecutors said.

Chacaguasay-Ilbis and Toaquiza rented an Airbnb and were captured on surveillance footage entering the Syracuse, New York vacation rental that afternoon. Three hours later, the suspect was allegedly seen on video carrying the victim's body out of the home. He returned to the house without her and exited once more wearing a new set of clothes, according to prosecutors.

Toaquiza's body was found June 22 in a Syracuse park after her family reported her missing.

Chacaguasay-Ilbis turned himself in to police Tuesday after a week on the run.

A motive in the slaying was not disclosed.

"She was a very sweet young lady with a bright smile and joyful personality," said loved ones, according to a GoFundMe launched to help offset funeral costs. "Joselyn was known for her kindness, warmth, and unyielding spirit. Her sudden and untimely death has left an irreplaceable void in our hearts."