* Norway mosque attacked by gunman
* Congregation members stopped attacker
* Young woman found dead at gunman's home (Releads with police statement)
By Lefteris Karagiannopoulos and Terje Solsvik
OSLO, Aug 10 (Reuters) - The man suspected of a shooting at a mosque in Norway may also have killed a relative before launching the attack, police said late on Saturday.
"A young woman was found dead at the suspect's address," assistant chief of police Rune Skjold told a news conference, adding that the man was suspected of murder.
Police earlier said a "young white man" had been apprehended following an armed attack at the al-Noor Islamic Centre near the country's capital, adding that members of the congregation had overpowered the gunman and stopped the shooting.
An older man sustained light injuries in the attack but it was too early to say if the wounds were caused by the gunshots or sustained during the attempt to restrain the gunman, according to police
An initial statement had said one person was shot in the attack.
The suspected attacker appeared to have acted alone, the police added.
"He is around 20 years old, a Norwegian citizen from the area," Skjold told Reuters.
"The man carried two shotgun-like weapons and a pistol. He broke through a glass door and fired shots," mosque director Irfan Mushtaq told TV2.
The shooter, who wore body armour and a helmet, was overpowered by members of the mosque before police arrived, Mushtaq added.
Only three people were present in the mosque at the time of the attack, preparing for Sunday's celebration of the Eid-al-Adha festival, which up to 1,000 people had been expected to attend, mosque spokesman Waheed Ahmed told Reuters.
The mosque earlier this year implemented extra security measures following the massacre of more than 50 people at two New Zealand mosques by a suspected right-wing extremist.
In 2011, anti-Muslim neo-Nazi Anders Behring Breivik massacred 77 people in Norway's worst peacetime atrocity, the majority of them teenagers at a youth camp. (Editing by Peter Graff, Kirsten Donovan and Jonathan Oatis)