Catherine, from Witney, Oxfordshire, has been travelling since September previous year and was reported missing on March 5.
Her belongings were left behind, said the Lucie Blackman Trust, which supports families of people missing overseas.
People searching for Ms Shaw said she left Hotel Mayachik twice; first at 01:37 local time, returned, then left again at 05:23 heading in the direction of Lake Atitlan.
The last sighting of her was at 5.30am, where she was seen carrying a puppy.
It later confirmed that the body was Catherine's.
We know that Catherine had been fasting for the days leading to her disappearance and that she had been disposing of possessions, including clothing.
Her parents also made a video appeal, which was posted on the charity's social media page.
The puppy was later found alone, shivering at the highest lookout of Indian Nose, a volcano overlooking Lake Atitlán, San Pedro and San Juan between 5am and 6am on Friday morning, the trust said.
The search has encountered many challenges including communication issues due to lack of power in the area.
Her friend, Jess Elizabeth, told The Tab: "She's a beautiful soul, loves nature, outdoors, looking after the planet, interested in permaculture, yoga, travelling".
He added: "We urge anyone who may have any information, no matter how small, to get in touch as soon as they can".
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.
Ms Shaw has been travelling since September past year and has previously visited Mexico and California in the US. "Please come home, sweetheart".