ORANGE -- Authorities on Friday identified the man and toddler who were killed in a quadruple shooting at a home in Orange Thursday afternoon.

Marcus Milien, a 21-month-old boy, and his uncle, Morlens Milice, 21, were sitting with others on the porch of a home on the 200 block of Cleveland Street when a gunman approached them and opened fire, Acting Essex County Prosecutor Carolyn A. Murray and Orange Police Director Todd Warren said in a statement Friday.

The child was pronounced dead on the way to the hospital, and his uncle was pronounced dead at 4:07 p.m. at East Orange General Hospital, authorities said.

Two others on the porch were shot, officials confirmed -- the toddler's father, who is in the hospital in stable condition, and a 15-year-old boy who sustained non-life threatening injuries, was treated at the hospital, and released, authorities added.

After the gunman started shooting, the group tried to run inside, and the shooter fled the scene, officials said. No suspects have been identified and investigators have not disclosed a motive.

Also on Friday, city spokesman Keith Royster said an unspecified "credible threat related to yesterday's shootings" caused a lockdown at Orange High School. Police were investigating and did not release further details.

Neighbors near the Cleveland Street crime scene said the area has been plagued with gun violence, including at least one other shooting earlier this week.

"They need to clean up Orange, because this happens all the time," said a woman Thursday near the home, who declined to give her name."Kids are afraid to even walk to school. It's been getting worse. I don't even want to come outside."

Another neighbor, who also asked not to be identified out of fear of retaliation, said he saw a man approach the house at the corner of Cleveland and Hawthorne streets around 3 p.m. carrying a gun. He heard about 15 shots within about five minutes before the man sped away in a dark color car, the neighbor said in an interview late Thursday.

"He's just a baby," another resident, Jensy Marcelin, said of the young victim. "Orange is bad right now."

The gunfire sent chaos through the largely residential area as children were being dismissed from a nearby elementary school. A crossing guard appeared to usher the children back to school as news spread of a shooting.

Police officers from departments around the area, including South Orange, West Orange, Montclair and Essex County sheriff's officers flooded the scene as a large crowd gathered near the shooting. Police blocked off a wide area around Cleveland Street as detectives processed the scene.

Orange Mayor Dwayne D. Warren called for an end to gun violence and asked residents to report criminal activity to the police.

"We lost two lives today in Orange, due to senseless violence which is all too common across our nation. My heart goes out to the families of the victims involved in this tragedy," Warren added in a statement issued late Thursday. "To prevent future tragedies in our city, we must become better neighbors and do something when we notice that something is not right in our neighborhood."

Warren referred questions about the homicides to the prosecutor's office, which is leading the probe.

Chief Assistant Prosecutor Thomas Fennelly confirmed that authorities found a burned Audi nearby that is being investigated to see what role, if any, it played in the shooting.

Officials have offered a $10,000 reward for information leading to an arrest and conviction in the homicides. Anyone with information is asked to call 877-TIPS-4EC or 877-847-7432.

Noah Cohen may be reached at ncohen@njadvancemedia.com. Follow him on Twitter @noahyc. Find NJ.com on Facebook.