CAIRO, May 8 (Reuters) - The Egyptian public prosecutor referred to court on Thursday a police captain accused of torturing a civilian to death, a prosecution source said.

The prosecutor accuses Captain Moetaz al-Lewag of detaining Mohamed Gomaa without good cause in a police station in Fayoum southwest of Cairo and then beating him to death.

Lewag denies this, saying Gomaa had a mental problem and hit his head against the wall repeatedly until he died.

International and local rights groups say torture is systematic in Egyptian jails and police stations. Past victims have reported receiving electric shocks and beatings.

The government says it opposes torture and prosecutes policemen when there is evidence.

Suspected police abuse gained widespread attention after a video circulated on the Internet last year showing a man being sodomised with a stick in a Cairo police station.

Two policemen were later sentenced to three years in prison for torture in that case. (Writing by Alaa Shahine, editing by Jonathan Wright and Mary Gabriel)