The NYPD is now offering up to a $2,500 reward for any information leading to the arrest of the person who left two infants dead behind a Bronx apartment building earlier this week.

Police sources confirm that both baby boys had skull fractures, which they say means the newborns could have been dropped out of an apartment window above the Claremont building's back patio.

The children were found dead, wrapped in paper on Monday.

Police are also investigating if someone from outside the building snuck back there to leave the infants.

Officials also say that the baby boys, who are possible twins, both had their umbilical cords still attached and didn't seem to have any cuts or bruises.

The medical examiner is doing a full autopsy to figure out the exact cause of death.

Police tell News 12 they are hoping someone from the neighborhood will come forward with information.

They say they are also trying to find DNA evidence that could give them any answer.