Police have arrested a man in connection with a double murder in San Francisco which left a third person fighting for their lives following the gun attack at a popular lookout.

The man from San Pablo was arrested in Richmond, although he name has not been released yet by police.

The attack happened at the Twin Peaks look out which offers stunning views of San Francisco bay shortly after 2am on Sunday.

Shot: Julio Peraza (pictured, left with his brother) was one of two men shot to death at Twin Peaks, San Francisco, on Sunday. The other were Rene Mora, 19. An 18-year-old was left fighting for his life in hospital

Police believe the gunman knew Julio Peraza, 21 and Rene Mora, 19, both from Santa Rosa.

A third person, an 18-year-old man remains in hospital after suffering life-threatening injuries.

Police said the suspect escaped from the scene in a carjacked GMC Yukon Denali which they recovered on Monday.

KNTV reported that the shooting area was popular with tourists.

Police have arrested a man on suspicion of shooting two people to death and badly wounding a third on Valentine's Day at a San Francisco lookout.

KNTV reports Monday that a San Pablo man was arrested in Richmond. His name wasn't immediately released.

He's suspected of killing two men shortly after 2 a.m. Sunday at the Twin Peaks lookout, a popular tourist spot with a sweeping view of the Bay Area.

Police say the gunman apparently knew and targeted 21-year-old Julio Peraza and 19-year-old Rene Mora, both of Santa Rosa.

An 18-year-old man who was shot and remains hospitalized with life-threatening injuries.

Authorities say the attacker fled in a carjacked GMC Yukon Denali that was recovered Monday.

Peraza's family have been hit hard. Speaking to KRON4, his brother Rafael said, 'I wish I could have one more day with him, let him know that he's loved.'

He added: '[Julio would] always try to put a smile on your face, make your day good even though he was going through that, sometimes, know know, but he would never show weakness.'

Julio had recently quit school and started working as a landscaper to bring in money for his family. His mother Sylvia told KRON4: 'He was a good son, he was a hard worker and he worked for his family. I'm going to miss everything about him. He was such a lovable son and he had a big heart.'

It is understood the Twin Peaks area, pictured, has been the subject of much violent crime in recent weeks

Peraza was shot dead at the Twin Peaks look out. Police said both dead men knew their alleged killer

The area has been troubled by robberies and thefts in recent times, but SF police district supervisor Scott Wiener told KRON4 that the police had particular problems with staff numbers.

'You can never predict when a crime will happen like that. What I will say is that overall as a city, we need more police officers and on Twin Peaks we need more security, because we've had a number of different crime problems in the area.'

Anyone with information about the shooting is being asked to call the San Francisco Police Department anonymous tip line at (415) 575-4444 or text a tip to TIP411 and start the text with SFPD.