Force India driver Paul di Resta has expressed his disappointment after retiring from the Singapore Grand Prix on Sunday.
The Scot crashed with just five laps to go as he battled for points at Marina Bay, which forced him to pull out of the race for the fourth consecutive outing.
"It's such a shame to come away with nothing to show from a race where we had put ourselves in a position to score some valuable points," Di Resta told reporters.
"I'm still not sure what happened, but I took the corner the same way as I had done the previous lap and the car went straight on and wouldn't stop. The team is investigating what happened."
Di Resta sits 10th in the drivers' rankings.
