Three teenagers arrested for sexually assaulting a 15-year-old girl who later killed herself were previously cited by police on lesser misdemeanour allegations following the incident.

Audrie Pott killed herself after she was allegedly sexually assaulted by three 16-year-old boys in September 2012. One of the boys allegedly took photos of the attack assault on his phone and shared it with the 15-year-old's classmates.

The three suspects face two felonies and one misdemeanour each, all related to sexual assault.

Authorities investigating the case have now revealed the three suspects were initially incited on misdemeanour allegations of sexual battery soon after the alleged attack. Preliminary investigations could only gather enough evidence to support the lesser misdemeanour sexual battery charges. And the three suspects were not taken into custody.

Lt Jose Cardoza of the Santa Clara County Sheriff's Department, told the San Jose Mercury News: "This was early on in the investigation, before more evidence and information was developed.

"If the information known to investigators later was known then, obviously they would not have been cited, they would have been arrested," Cardoza added.

Police have now gathered more evidence following examinations of the suspect's commuters and mobile phones. Lawyers for the 15-year-old's family claim the boys performed a serious of sexual acts on her while she was passed out at a house party in Saratoga, California.

Lawyers also say one boys took pictures of the attack on their phones which then "spread like wildfire", even ending up on Facebook.

Eight days after the alleged sexual assault, Audrie posted on her Facebook that "the whole school knows" and that her life was "ruined".

The Saratoga High School pupil was then found hanged at her home.

Took deliberate steps to destroy evidence

Classmates of Audrie's at the Californian high school are now downplaying claims that the photo were widely seen by the pupils. Samuel Liu, an editor at the campus newspaper, the Falcon, said: "The photos never went viral."

"I don't believe many saw the photo at all."

Following the 15-year-old's death, her family set up the Audrie Pott Foundation to provide music and art scholarships and offer youth counselling and support.

On its Facebook page, the foundation wrote a post repeating allegations that the suspects could have destroyed evidence after the alleged assault.

The post said: "We suspect that the boys who we believe are responsible for Audrie's death took deliberate steps to destroy evidence and interfere with the police investigation.

"If students have information about this crime, if they saw pictures or know anything that will assist in bringing these young men to justice, please come forward."

The case echoes of 17-year-old Canadian teenager Rehtaeh Parsons, who killed herself following months of torment after photos of an alleged rape in 2011 was circulated around school.

Following public outcry over the incident, Nova Scotia's justice minister appointed four government departments to look into Rehtaeh's case after police originally said there was insufficient evidence to charge anyone.

Hacktivist group Anonymous claim to know the identities of the alleged attackers. They have threatened to name them if the Royal Canadian Mounted Police do not charge anyone with the alleged attack.