The English Assassin by Daniel Silva is the second story in the Gabriel Allon series.
This novel had a publication date of March 4, 2002.
The English Assassin book description
When art restorer and occasional Israeli agent Gabriel Allon is sent to Zurich, Switzerland, to restore the painting of a reclusive millionaire banker, he arrives to find his would-be employer murdered at the foot of his Raphael.
A secret collection of priceless, illicitly gained Impressionist masterpieces is missing.
Gabriel’s handlers step out of the shadows to admit the truth – the collector had been silenced – and Gabriel is put back in the high-stakes spy game, battling wits with the rogue assassin he helped to train.