The accident occurred early on Friday morning, local police say
The arrestees are Md Saheb Ali, 34, from Jhenaidah and his wife Jesmin khatun, 25.
Jesmin had brought home the teenaged relative to look after her child recently, said Md Sajedul Islam Sajal, a senior assistant superintendent of police at RAB-4.
Later, Saheb Ali allegedly raped the girl with Jesmin’s help, Sajal said.
RAB arrested the couple on Saturday afternoon in an operation after the allegation surfaced, the RAB official added.