MILAN - Italian tax police said on Wednesday they seized documents from units of motorway operator SIAS, following the collapse last month of a bridge after a massive landslide caused by heavy rains in the northwestern region of Liguria.

Police visited offices of SIAS units Autostrada dei Fiori in Turin and Sina in Milan and the coastal town of Savona and took documents relating to the collapse of the bridge on the A6 highway near Savona on Nov. 24.

No casualties were reported. The fall of the bridge highlighted concerns about the safety of Italy’s crumbling motorway infrastructure following the collapse of the Morandi bridge in Genoa last year that killed 43 people.

Police said in a statement that they seized documents about “engineering, construction, regular inspections and maintenance” of the bridge.

No comment was available from Autostrada dei Fiori, SIAS or from SIAS’ parent company, Gavio.

Prosecutors in Savona have opened a criminal investigation following the Nov. 24 incident, without identifying any suspects.

On Tuesday, tax police searched offices of Atlantia’s toll roads unit and said they were opening a new line of investigation into motorway safety barriers following the deadly collapse of the Morandi bridge.