### Clue: Criminal returned seascape artist's unfinished night scene (8)
### Answer: NOCTURNE 
 ### Explanation: Definition: night scene
 **Reversal of**(… returned) CON(short for "convict"/a criminal) + "Turner"(William, an English Romantic painter, who often pained seascapes/marine art) **minus ****its last letter**(…'s unfinished).