Relatives of missing Ben Needham from Sheffield fear allegations of a police drinking session on Kos will jeopardise the search.
Ben's mum and sister defended South Yorkshire Police officers after they were photographed on a night out on the Greek island of Kos on the day they launched a fresh appeal for information.
A team of detectives travelled to Kos earlier this week to re-appeal for information on the whereabouts of Ben and to follow up lines of enquiry.
They also announced a £10,000 reward for information leading to the discovery of Ben, who was 21 months old when he went missing while he was playing outside a remote farmhouse his grandfather was renovating.
Some of the police trying to find Ben were photographed over an eight-hour period and were seen drinking lager and wine until the early hours of Wednesday.
A senior detective, believed to be Det Supt Fenwick, has been summoned to the UK to face questions from bosses.
Det Supt Fenwick said: “We were hardly drinking. We're not going out and drinking loads of alcohol.
“Can I just say there is no alcohol on public money.
“We're desperately trying to find Ben over here and we're working really hard."
Ben's sister, Leighanna Needham, said the publicity surrounding the night out was unnecessary.
"Those officers go above and beyond their call of duty for us as a family and I am utterly seething that this could have potentially ruined their investigation," she said.
"They are human beings like you and I. They deserve a god damn drink the hard work they have put into this.
"Our detectives fund their own personal expenses when they are off duty.
"Those detectives on that island are the only official help we've had from this government in 25 years."
Ben's mum, Kerry Needham, added: "They work so, so hard, putting every ounce of energy into trying to find out what happened to Ben and for this to come out, it could hinder the case.
"I know that without these officers we will not find the answers to Ben. I am so angry about it.
"No-one can understand how much hard work these officers put into this case. It is very, very cruel what has happened."
She said she 'fully' supported the police team and disagreed with the decision to send a senior officer home.
"Matt Fenwick is an amazing detective; he has been by our side for a few years now and we have never had any problem with his work," she added.
"These police officers, they are human beings at the end of the day. What they choose to do in their own time is their business, not anybody else's.
"It is horrendous. I can't believe what has happened. We work together - the police, the media and myself, we work together as a team. This is just not team work.
"We are supposed to be trying to find the answers to what happened to Ben along with these detectives, and this could just hinder it. And I'm angry this report had to come out, it is just not nice."
A South Yorkshire Police spokesman said: “The team in Kos have been working on investigating the disappearance of Ben Needham for a number of years.
“We're absolutely committed to this investigation and require the highest possible standards from all of those involved. The team must now get on with the important task in hand.
“Following concerns raised regarding the behaviour of some of those involved the senior officer has been recalled to the UK with immediate effect to provide the details of exactly what has happened.
“An internal investigation will follow.”