During that awkward half-hour of no-driving downtime in Fast & Furious, Dom gets to unleash his inner-Batman by visiting the scene of Letty's apparent death and having a poke around. He looks at the skid marks on the road to hypothesise how Letty died, and then find some Nitrometh residue on the pavement. Coincidentally for him, only one person in all of LA sells the fuel (probably the most ridiculous thing in the whole movie), so Dom pays him a visit and threatens him for information. It's not that one assumes Dom is just a braindead meathead, but does anyone really want to see this sort of breadcrumb-following nonsense in a Fast & Furious movie? No thanks.