Nicholas Mockford's ExxonMobil role provides few clues as to a motive And of all its operations, those where Nicholas Mockford worked in Brussels, managing the marketing for part of the company's Chemicals division, seem, on the face of it at least, particularly innocuous. ExxonMobil said on Friday that it had "no indication" that his being gunned down in a street in an assassination-style killing was related to his work. While ExxonMobil declined to give further details of his role, sources close to the company suggest Mr Mockford - despite being a departmental manager and working with the company for several decades - was not as senior as he might appear. There is no mention of him on the company's website. Mr Mockford appears to have delivered a speech two years ago to an ExxonMobil-sponsored conference in Shanghai on the subject "Phthalate Plasticizer Alternatives: Facts versus Fiction" - suggesting his speciality was in substances used to make plastics such as PVC more flexible and durable. The subject is, in fact, a controversial one - some phthalates have been partially banned in the EU and the US because of health fears. ExxonMobil makes alternatives to phthalate plasticizers but, as a major producer of the substances, was also known to have lobbied strongly against the bans over recent years. Nevertheless, while more politically controversial than it might first appear, it is hardly the corner of the oil industry in which one might expect to cross the path of a gun-toting killer. No wonder, then, that those working at ExxonMobil's UK headquarters in leafy Surrey say Mr Mockford's brutal murder has sent such shock waves though the company.