How did the CT cop, the Columbo clone, link the rental car to the "accident"? Did someone report seeing it at the marina?
What are they doing? Why do they come here?
Some kind of instinct, memory, what they used to do.
Graham's lighter. He lit a cigar in the rental car and left the lighter on the dashboard, then forgot it when he turned the car in.
The car rental attendant found it and pocketed it, in order to send it back to the person of record for the rental--George. It was rented with George's car rental credit card.
The detective already was suspicious of Graham due to firt his wife dying and then the boat blowing up with the guy on it who beat out Graham for his promotion.
So the detective was starting to connect the dots.
They became more connected and he stepped up in investigation after the detective double checked with George about the rental car---and George said no, he had not rented a car that night.
Ergo...Graham was back in the frame again for a sudden death. Then the lighter appeared and started making the rounds with the detective aware it had been found---and Stella of course then told the detective Graham has lost it.
At that point it all tied together---the boat, lighter, George not renting the car....the rope was tightening on Graham.
okay, but how did the detective in the first place know that some random rental agency found the lighter? After all, Graham was not involved in the crime
shareDidn't Stella tell him when she called him?
Cannot recall if we heard everything Stella told him, we just saw her fingering his card and the lighter and we presumed I guess that she called and filled the detective in on the fact that a lighter was returned to George's name at the ad agency...
This sharp-eyed viewer hit upon a good point. First off, how did they even know about a rental car?
There are a couple of possibilities.
1) Somebody at the marina saw it. After the explosion, the place would be swarming with cops and media asking people if they noticed anything suspicious. Worth noting: When Caine leaves the marina, we're given a clear shot of the car's New York license plate. The director could have shot the car driving off from any angle, but that was the one chosen. Also, the detective works for the CT state police, so I'm assuming the boat was docked in CT.
2) Somewhere along the line, George Brewster was viewed as a suspect. After all, he told Caine he wanted Bob to die. Who else did he tell? The police could have (somehow) looked through Brewster's records to (somehow) find out that he rented a car. Assuming a witness at the marina did not flag the car, the detective could still circumstantially connect it to the crime: If the rental place keeps careful mileage records, the detective could prove that the distances line up.
Between the two possibilities, the first seems more plausible. I'm not sure this qualifies as a major plot-hole because it would've been trivially easy to show some nosy person at the marina. If they had, it would undercut Stella's cetnral importance to the story later on.
MavKilledGoose's second theory is supported by the film.
Laker (Patton's cop) was looking into Graham and George as suspects. He kept after Stella because she was Graham's sole alibi. He must've checked into George, too, and learned about the car rental through his credit records. Car rental on the night of an out-of-the-city murder warrants further investigation, so he asks George who denies renting a car.
He checks with the rental company and learns that whoever rented that car left a lighter that had been mailed back to the office.
That's why he kept asking Stella about the lighter, and why Stella herself focused on the lighter as the critical clue.