In a statement The Lucie Blackman Trust, which has been helping Ms Shaw's family, said it was "saddened to announce that a body has been found in the search for Catherine Shaw".
Guatemalan police, local residents and British people in the country helped search for Shaw near the area where the puppy was found over the weekend.
Three search teams have been active around the location but nothing has been found.
It has also been confirmed that she did not have a tattoo on her ribs.
Facebook posts analysing photographs of poor Catherine's body are totally unacceptable.
Formal identification has not taken place but Ms Shaw's family have been informed of the find. "Please respect their privacy at this hard time".
The Lucie Blackman Trust said Shaw had left the Eco Hotel in Mayachik, near San Pedro and San Juan, on 5 March at 1.37am, but then returned at 3.19am.
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Shaw headed towards the lake when she left the second time, and did not return.
We know that Catherine had been fasting for the days leading to her disappearance and that she had been disposing of possessions, including clothing.
A puppy which Ms Shaw took with her when she left the accommodation was found at the peak of the hiking trail on Friday morning.
Other challenges in the search also included communication issues due to lack of power in the area.
Shaw's friend, Jess Elizabeth, wrote on a Facebook page dedicated to finding Shaw that the backpacker had "no belongings with her, passport, money or mobile phone - they were left at the hostel".
The woman's father had arrived in Guatemala to assist the search for Shaw, the British Embassy confirmed, adding that it was supporting the family and authorities. "Please come home, sweetheart".
The trust had received many sightings of female travellers matching Ms Shaw's description and had to work through several leads.