Staff at the Recycling First charity discovered the bricks had been removed from the back of their building when they returned from the Christmas break.
The crooks are believed to have crawled through the hole at the charity building, in Macmerry, East Lothian, and made off with small items of furniture and bric-a-brac during the raid, which mirrors two previous break-ins.
Thieves stole around £10,000 in cash from homeless charity Edinburgh Furniture Initiative’s (EFI) base in Sighthill just before Christmas, while thousands of pounds worth of knitwear were taken from the Cashmere Barn, in Fenton Barns, East Lothian, eight weeks earlier.
Recycling First manager Tom Logan admitted he was still “shell-shocked” at his charity being targeted by the crooks.
Mr Logan, 56, said: “We finished up on December 19 and were in a couple of times over the holidays, but it is not the sort of thing you come and check. Fortunately we do not hold cash on the premises overnight, and they only managed to get away with small items of furniture and some bric-a-brac.
“One of our volunteers was coming back from walking his dog and he noticed the hole [at the back of the building].
“If they are desperate we would just give them the items for nothing – we have done that in the past.”
The charity, which has been running for around ten years, offers furniture to the needy at low prices.
Mr Logan added: “We are a charity and everything we take in is donated. We then hand back to the homeless and people on benefits in East Lothian.”
Police are investigating all three break-ins but are refusing to make any connection. A charity worker, who wished to remain anonymous, added: “The police might be saying the robberies are not connected at the moment, but it seems inconceivable that there are three separate gangs involved in these crimes.
“It certainly looks like the same lot are responsible and I hope they are caught before they strike again.
“It really is disgusting that they are targeting organisations who do charitable work for their local communities.”
Just before Christmas, a gang of masked raiders used sledgehammers to break through a 1ft-thick wall at the EFI base in Sighthill Industrial Estate.
They then crawled through the hole in the brickwork and ransacked the office before ripping out an 80kg safe which had been bolted to the floor and contained £10,000.
A Police Scotland spokesman said: “The [Recycling First] incident occurred between 5.30pm on December 19 and 12.30pm on January 5. Staff returned to work on Monday, January 5, to discover that a suspect, or suspects, had broken into the unit.
“Anyone who remembers seeing anything suspicious over the festive period, or who has information that can assist officers with their investigation, is asked to contact 101.”