Basirhat: A woman allegedly mixed sleeping pills in her husband's food and strangled him in front of their two-and-a-half-year-old daughter in Basirhat, North 24-Parganas, on Thursday night.

Shilpa Debnath, 24, was arrested after family members of Kamal, 26, found his body lying on the bed. They said they had caught the accused when she allegedly tried to run away.

Police said after a preliminary investigation that Shilpa had an affair and she decided to murder Kamal after he came to know about it.

Shilpa and Kamal, who worked as a cook at a restaurant in Bangalore and occasionally visited home, got married five years ago.

"Kamal came to know about Shilpa's affair after his last visit home around 20 days ago. We learnt that Shilpa had been in a relationship with the man since before her marriage," an officer of Basirhat police station said.

Kamal's family members told the police that the couple would often fight over the past few days.

"Other family members became suspicious on Thursday night as they did not hear Kamal's voice for some time. Around 11pm, they asked Shilpa what he was doing. The woman said Kamal was sleeping. They then entered the couple's room and found him lying on the bed. One of the family members touched Kamal and realised that he had died," the officer said.

Shilpa allegedly tried to run away but the family members caught her and alerted the police.

Shilpa apparently said during interrogation that she had mixed sleeping pills she had bought from a neighbourhood medicine shop over the past week with her husband's food on Thursday night.

"Kamal passed out after dinner. Shilpa then strangled her," the officer said.

"After murdering her husband, Shilpa placed the body in a way that it would appear Kamal was sleeping. A pillow was placed under his head and his hands were kept on his chest. Shilpa killed her husband in front of the couple's two-and-a-half-year-old daughter," another police officer said.

The police said Shilpa had called her lover and told him about the murder.

The police suspect Shilpa had planned to flee with the man and was waiting for the family members to fall asleep.

"We are interrogating the woman's lover and trying to find out whether he was involved in the conspiracy," the officer said.