The operator of the boat that capsized in New York Harbor on Aug. 8, killing a 27-year-old mother and her 5-month-old child, pleaded not guilty Thursday, according to officials.

Manuel Ernesto Hernandez-Urmana, who was also arrested by U.S. Immigration and Customs Enforcement in Manville, New Jersey, pleaded not guilty to two counts of misconduct and negligence and could face up to 20 years in prison if convicted on both charges.

The New York Police Department first took Hernandez, 46, into custody on 13 counts of reckless endangerment on Aug. 9, after the 22-foot Yamaha speedboat overturned near Liberty Island. He was moved to federal custody that same night.

The victims, Sara Sánchez, a Queens resident, and her daughter, Antonella García, were pronounced dead after they were taken to a hospital. Twelve other people were rescued from the water and were in stable condition, according to the U.S. Coast Guard.

Federal authorities blamed the incident on an overcrowded boat–with 14 people on board, exceeding the maximum capacity of 10 people–, a lack of proper licensing and the failure to put a life vest on the infant.

Prosecutors said Hernandez, originally from El Salvador, made a U-turn that brought the boat into a swell. He accelerated to pass through it, but the swell swamped the boat’s bow and caused it to overturn immediately.

Hernandez, of Manville, New Jersey, will be detained at the Metropolitan Detention Center as his case moves forward.