"I was the one who found [the man] and convinced him to walk out," the resident said.
Police confirmed the acquaintance was present when they arrested the man but were still trying to verify other details.
They have interviewed him and are expected to talk to him again.
The acquaintance said there was "more to the story" but he could not comment any further.
He did not want to "tread on the family's toes" or obstruct the court process.
He also said he had been offered money by another media organisation to tell his story.
The arrested man, who lives in the region, appeared before Levin District Court on Wednesday charged with carrying a knife on Forest Rd.
That's in the area where the search for Alex was focused.
He was remanded in custody by consent until next Wednesday.
The court heard he is likely to face at least one further unspecified charge.
'We are devastated by the sudden loss'
The family of Alex Fisher have expressed their gratitude to the Waiterere community for all the help offered during the search for the 10-year-old boy.
"As you can imagine, we are devastated by the sudden loss of a beloved son, brother, grandson, uncle, nephew, cousin, classmate, friend, and fellow Scout."
The statement shared on behalf of the family today went on to thank those involved in the search for Alex and for the donations of "food, money, time and prayers.
"It is really appreciated and shown the family how terrific our local community and country as a whole really is," the family said.
"The Fisher family have a long association with Waitarere Beach, Alex's grandmother lived there for over 27 years.
"The family have had many lovely and memorable occasions at the beach."
The family said no further comments would be made and again requested privacy.
READ MORE: Tragedy of Alex Fisher - Discovery of boy's body in sand dunes nightmare for family
A vigil for Alex will be held on the beach this Sunday at 7pm.
A blessing is taking place on the beach where the body of 10-year-old Alex Fisher was found yesterday.
Twenty people, including kaumatua and several police officers, are now standing on the dunes and paying their respects, with heads down.
Maori elders and Manawatu area commander Inspector Sarah Stewart have just arrived outside the Rua Ave house near the place Alex was found to perform a blessing.
Ministry of Education head of sector enablement and support Katrina Casey said a traumatic incident team was at Alex's school yesterday, and met with staff today to ensure they felt confident to support children when they returned to school on Monday. The team would be back at the school on Monday if required.
'Whenever a school experiences a distressing incident, of whatever kind, we offer the support of a traumatic incident team that goes into the school to offer whatever help is needed.
"The team's role is to help the school return to its normal day to day routines.
The team talk to staff, the principal and board members. They brief staff on how students may respond to this difficult event and how to get access to additional specialist psychological support if it's needed for any individual students or staff members. That support is there for as long as a school needs it."
The ministry could provide extra resources to support the school if needed.
"This could include relief staff who work alongside teachers or take on duties that will free up school staff to support and respond to the needs of the children."