CASTRO VALLEY, Calif. -- An autistic eight-year-old Castro Valley boy was safe at home Tuesday night thanks to neighbors pitching in to help rescue teams during a frantic search to find the youngster before night fell.

The boy's mother said he wandered away from their home on Princeton Place earlier in the day. It was one of the boy’s neighbors who eventually found him. The boy's parents expressed gratitude Tuesday night to their neighbors and rescue crews.

Eight-year-old Ingvar Slettnes arrived back home, showing no signs of the ordeal that sent an entire neighborhood and dozens of rescue crew members on a frantic search for him after he wandered from his home.

At about 1:30 p.m. Tuesday afternoon, the boy's mother Limin Tseng said she was preparing lunch and saw Ingvar playing in the yard. A moment later she looked up and he had vanished.

"In the past, he went out a few times in the street as well, but he always came back," said Tseng. "Usually in five or ten minutes, he's on his way back."

Tseng said her son has very limited language skills and is unable to ask for help. When she couldn't find him, she called 911 and asked neighbors to search.

"This is an incredible neighborhood," she said. "Every house on this street went out looking for him."

Neighbor Eddie Villasenor said he got home from work at about 4:30 p.m. and joined the search. Villasenor said he was hiking down a ravine calling out the boy's name when he heard a noise about 100 yards down below in a creek.

"He was playing and splashing in the water," Villasenor said.

Dozens of emergency workers were also in the area searching for the boy. Once Villasenor located Ingvar, they moved in to carry him to safety.

But the Alameda County Sheriff's department credited Villasenor for his sharp ears, saying the boy easily could have been injured.

"There are wild animals in the area and it gets cold at night," Alameda County Sheriff's Department spokesman Sgt. J.D. Nelson said. "You're racing against time. You know the sun's going down and you have to rescue that child before nightfall."

The boy's parents told KTVU their son did not suffer any injuries. Now they said they'll try to figure out how to keep him from wandering off again.