“And which. And who. These forms are incorrect unless the relative pronoun has been used previously in the sentence. ‘The colt, spirited and strong, and which was unbroken, escaped from the pasture.’’John Smith, one of our leading merchants, and who fell from a window yesterday afternoon, died this morning.’ Omit the conjunction.”
Excerpted from: Bierce, Ambrose. Write it Right: A Little Blacklist of Literary Faults. Mineola, NY: Dover, 2010.