Maddox Ritch vanished from Gastonia's Rankin Lake Park around 1:30 p.m. on Saturday
Credit: Courtesy Ian Ritch

It’s been more than three days since 6-year-old Maddox Ritch disappeared from a North Carolina park. Now, the boy’s father, Ian Ritch, says he’s overcome with guilt, wishing he had done things differently on that fateful day.

Maddox, who has autism and limited verbal skills, was walking with his father and another adult at Gastonia’s Rankin Lake Park around 1:30 p.m. local time on Saturday when he took off running. Maddox hasn’t been seen since, and more than a dozen law enforcement agencies have launched a days-long search to find the little boy.

“These past few days have been hell for me. I’m so broken. I’m heartbroken,” Ian, 42, of Concord, tells PEOPLE. “Every time it gets dark at night I burst into tears because I’m thinking, ‘My little boy is out there alone.’ The longer [the search is] going the harder it gets because I’m so worried. He hasn’t had anything to eat or drink.”

Ian says he and his friend were walking with Maddox near the lake when the playful boy took off running behind a jogger. It’s common for Maddox to run around, so Ian allowed the boy to jog ahead for fun, he says. But when Maddox began running faster, Ian says he took off after him and wasn’t able to catch up with his son before losing sight of the boy.

Ian (left) and Maddox Ritch
| Credit: Courtesy Ian Ritch

“I was terrified. I didn’t know which direction he went so I looked as hard as I could, I went different ways and everything,” the grieving father tells PEOPLE. “I tried to find him. I don’t know where he went. Usually when he takes off running he’ll slow down and stop for me to catch up with him. This time he never stopped.”

Ian says park staff helped him search the area before calling police. He contacted Maddox’s mother, Carrie Ritch, who was “hysterical” when he broke the news.

During a press conference Tuesday, Carrie said: “Maddox is my whole world and my reason for living.”

“If you were at the park Saturday and saw Maddox … please, urgently, please call the tip line,” she said through tears. “I want my baby back in my arms.”

A $10,000 reward is now being offered, authorities added.

Maddox is 4’0″ and was last seen wearing an orange T-shirt that read “I am the man” along with black shorts. The National Center for Missing and Exploited Children is also assisting in the search, and officials wrote on the site that Maddox may be in need of medical attention.

Credit: Gastonia Police Department

In a Facebook post on Monday, Carrie wrote that authorities are doing all they can to find her son.

“My main focus is bringing him home. Thank you all for your love and support. I am completly (sic) heart broken. I need him home. I want him in my arms. I want to see his smile and hear his precious laughter. I know God is with him protecting him.”

Carrie did not immediately respond to a request for comment from PEOPLE. City officials confirm to PEOPLE that she and Ian are cooperating with police in the investigation.

FBI officials in Charlotte have also joined the search, and one agent, Jason Kaplan, said in a weekend news conference that authorities are working to determine whether Maddox was abducted or is simply lost.

Credit: FBI

“I was thinking he was lost in the woods, now I’m not so sure,” Ian tells PEOPLE. “They’ve been looking for days and haven’t found anything. I’m starting to worry. It’s been too long. They had so many search and rescue [teams] that they should have found him by now.”

In the days since the incident, Ian says he’s been overcome with guilt, adding that feeling at fault has only added to his heartache.

“People are making it out like I did something to him. I would never hurt my little boy. I love him to death and I just want him back. I’ve been feeling the blame since this happened. I just wish I would have caught him before he got too far away from me. It’s broken my heart to think that I just let him get too far away.”

Ian and authorities have urged anyone with information to call the police department’s tip line at 704-869-1075.