Arthur Morgan III remained at large despite a dragnet involving 13 law enforcement agencies including the FBI. Authorities believe the 27-year-old Morgan, of Ocean Township, may have left the state.
The victim, Tierra Morgan-Glover, lived in Lakehurst with her mother and was having a court-approved visit with her father on Monday, but he never took her back. The girl's body was discovered Tuesday in Wall Township, about 20 miles north of where she lived.
"This is an unspeakably awful tragedy," Monmouth County Prosecutor Peter Warshaw said. "It appears to be senseless and without reason."
The toddler was discovered by children playing in Shark River Park, said Christopher Gramiccioni, a spokesman for the Monmouth County prosecutor's office. The children notified park rangers, who called police.
A 911 call was received by police at 2:28 p.m., saying that "student-aged children came across what they were concerned was a child in the creek," Gramiccioni said.
Police found the girl's body, still strapped in the car seat, partly submerged in the creek, a tributary of the nearby Shark River. The creek is 3 to 7 feet deep in the area where the body was found, near a roadway overpass about 15 feet above the creek.
Warshaw would not say whether authorities believe the girl was thrown from a vehicle into the creek, or whether she was carried into the park and placed in the water.
An autopsy conducted by the county medical examiner's office determined the cause of death as "homicidal violence, including submersion in water."
A warrant from Ocean County charging Morgan with child endangerment and interference with custody had been issued before the girl's body was found.
Transit police agencies, including NJ Transit, Amtrak and the Port Authority of New York and New Jersey, were assisting the FBI and the U.S. Marshals Service in a search that included train and bus stations, airports, highway bridges and tunnels.
Morgan was last seen on a platform of the Asbury Park train station Monday night between 7 and 8 p.m., the prosecutor said. His last permanent address was at an apartment in Eatontown, but Morgan had been staying on and off with a friend in Ocean Township, just outside Asbury Park, the prosecutor added.
"The police are working with every ounce of their being to locate him," Warshaw said.
No one answered the door Wednesday afternoon at the Lakehurst home where the child had lived with her mother, Imani Benton. Earlier in the day, the child's grandmother, Michelle Simmons, told The Star-Ledger of Newark the family is having a hard time coping.
"We are just trying to get through this," she said. "It's very difficult."
The death of the toddler marks the second time in two years that a young girl has died under such circumstances in New Jersey.
A former Galloway Township man is awaiting trial on murder and kidnapping charges in the drowning of his 3-month-old daughter in February 2010, when he is accused of throwing the infant off a bridge on the Garden State Parkway.
The baby's body was found several weeks later along the banks of the Raritan River. The mother had sole custody of the child and was seeking a restraining order against the baby's father at the time of the abduction.