Nearly a month after 5-year-old Dulce Maria Alavez disappeared from a New Jersey park, the reward for any information leading to her return has jumped to $52,000, authorities announced.

Unions representing New Jersey State Police troopers and officers have altogether contributed $10,000 to the reward, Bridgeton Police Chief Michael Gaimari said in a Facebook post.

Philadelphia Lodge #5 Fraternal Order of Police offered an additional $5,000 Friday, and two other donations of $1,000 each were confirmed Monday, according to Gaimari.

Still, authorities have struggled to make a break in the case — despite the extensive investigation, Gaimari said.

“Investigators continue to follow leads in the case and have gathered a substantial amount of information through interviews and technological means,” he said. “However, we are in search of key information that we believe exists through the public that would greatly assist the investigation.”

The search for the child has spanned more than 200 locations — including abandoned buildings and desolate areas, Cumberland County Prosecutor Jennifer Webb McRae said last week.

Over 1,000 tips were received and processed, and more than 500 vehicles have been identified and investigated, she said. Additionally, more than 50 different types of legal process have been served, including court orders and subpoenas.

McRae emphasized that immigration status shouldn’t prevent potential tipsters from coming forward.

“If you are a part of the undocumented immigrant community, you don’t have to be fearful of providing information,” she said. “Our Governor and Attorney General have reiterated what we have already said, in New Jersey if you are a witness, law enforcement cannot and will not ask you about your immigration status.”

Investigators believe Dulce was abducted from the 1,000-acre Bridgeton City Park on Sept. 16 as she played with her 3-year-old brother, Manuel, at a playground while their mother waited in a car.

Moments later, Manuel said his sister was gone, pointing toward several storage buildings nearby.