HONOLULU -- Honolulu police said they are investigating the death of a baby on the H-1 Freeway.

Witnesses said that they saw a man throw the infant from the Miller Street pedestrian overpass, but police said they are not sure if the child was alive or dead when the man threw the child. It appears the child was hit by at least two cars, officials said.

Police arrested Matthew M. Higa, 23, nearby on Prospect Street. They took him to the Honolulu Police Department's cellblock.

The man was wearing hospital scrubs. Officials from Queen's Medical Center, which is located near the scene, said he is not a patient.

As the man was taken away by police, he yelled, "Thank you for everything" to KITV camera crews. (Read more about Higa.)

Police said they are not sure where the infant came from, and they are checking local day care facilities in the area to see if anyone is missing a child.

H-1 Freeway was closed at the Vineyard Boulevard off-ramp, routing traffic onto city streets. Police reopened all lanes of the freeway at about 4:30 p.m. The police had kept the mauka most lane in the Ewa-bound direction between the Lunalio offramp and the Miller Street overpass closed as crews clear the scene.

Major backups were reported on all surface streets. Motorists said the main roads in Honolulu, such as King Street were gridlocked with traffic, moving at a very slow pace.