Hundreds of parcels awaiting delivery were rifled through in a warehouse over the Christmas weekend.
Thieves broke into the premises in Whiteside Industrial Estate, Bathgate, between 5pm on Christmas Eve and 7am on Tuesday.
Police said it was “obvious” that they knew what they were looking for with officers suspecting the criminals were inside the warehouse for some time opening hundreds of packages and stealing “a quantity of goods”.
The thieves had targeted the premises before, Police Scotland said, but returned to commit the theft.
The force appealed for help urging anyone who saw anything suspicious to get in touch.
Constable Chris Watson said: “We believe that the thieves, who had previously targeted the warehouse, returned and stole the goods. It’s possible they had been in the premises for a while as hundreds of parcels, awaiting delivery, had been opened with the contents of some stolen.
“At the moment we do not know the value of what has been taken, but it’s obvious that the thieves know what they were looking for.
“If you have any information about the housebreaking, or were maybe in the area over the weekend and saw something suspicious, then please contact police via 101 quoting reference number 0522 of Tuesday, December 28, 2021.”