Police don't think a letter from Tom Phillips is recent, or relevant to their search for him and his three children.

Their mother, Cat, posted the letter on social media, while begging the public to help.

Searches around Marokopa continue, with the $80,000 reward for information expiring in five days.

Newshub reporter Karen Rutherford is in Marokopa - and she says there are strong indicators an end to the search is near.

"They know who they're looking for and they know who they're targeting with this $80,000 reward. They are hoping that someone in that wider circle will cave."

LISTEN ABOVE

• 'I have a good heart': Mother of Marokopa kids releases letter from fugitive dad
• Marokopa fugitive dad Tom Phillips: Police reveal 12 more sightings
• Police contacted with claims of information on missing family after reward issued
• Authorities suspect people assisting missing Marokopa man
• Still armed and dangerous: Tom Phillips hiding in or near Marokopa, cops say
• Police checkpoints set up around Marokopa as Tom Phillips search intensifies
• 'Not the actions of a good father' - Police say missing Marokopa man armed, still a risk to the community