The American Compendium of British Crimes by William Ruby

As the discussion heated into a quarrel, Malcolm finally proclaimed that the customs officials had no legal authority to open the cellars, and if any one of the men tried, he'd “blow his brains out.” Malcolm then donned a sword and two pistols and repeated the threat. When summoned for the key, MacKay objected, protesting that these were “very extraordinary proceedings to search private dwelling houses.” More men showed up from British customs, and MacKay and Malcolm grew agitated. Malcolm permitted the search, but refused to allow Hallowell to search a locked cellar, which he said belonged to his business partner, William MacKay. The search was based on a tip from a confidential informant that Malcom possessed wine and spirits in violation of the Stamp Act. Compared to modern search warrants, writs of assistance were essentially permanent - they remained in effect until six months after the death of the King in power when they were issued. He could also transfer the writ to another party. A writ also gave its holder the power to search any building or residence and confiscate any suspected contraband. Writs of assistance not only gave British customs agents the power to search for illegal imports, but as the name suggests, it allowed them to command other government officials - and even private citizens - to assist them. And they weren't really issued in the colonies either until a century later, when England instituted a new round of taxes and import restrictions. These warrants were first authorized by the British Parliament in 1660, but they were rarely utilized in Britain.

Writs of assistance were a type of general warrant issued specifically to inspect for smuggled goods.The writs gave customs officials the power to enter private homes and business to search for smuggled or untaxed goods.

The American Compendium of British Crimes by William Ruby