Kolkata, Nov 20 (IANS): A youth arrested on charges of theft in Kolkata, who died in police custody on Friday, was beaten to death, his family members have alleged.

Fardin Khan, 20, a resident of Iqbalpur in Kolkata, was arrested for allegedly trying to steal a mobile phone around 10 days ago.

He was twice taken into police custody -- for 10 days in Presidency jail and then for a day in Kolkata Police Headquarters at Lalbazar.

Fardin was admitted to the state-run SSKM hospital on Friday evening in a serious condition. The hospital authorities declared him dead on Friday night due to multiple organ failure.

Fardin's family members have accused the police of brutally beating him inside the lock-up of Lalbazar police station.

"My son was alright when we last met him in Presidency jail four days ago. What could have happened to him in just four days that he died! We think he died as he was brutally beaten in Lalbazar police lock-up," Fardin's mother Imtiaz Begam said.

Fardin's family also claimed his body had deep bruises caused by beating.

The police, however, denied the allegations.

"Fardin was heavily addicted to drugs. He was suffering from withdrawal syndrome in police custody," a police officer from Lalbazar said.

"We shall investigate the matter," Joint Commissioner of police (Crime) Vishal Garg said.