The two 17-year-olds arrested for allegedly sexually assaulting a 13-year-old girl at a Mountain View park are being charged as adults, according to the Santa Clara County district attorney's office.

Both teens, along with a third suspect -- a 20-year-old man -- are being charged with committing a "lewd or lascivious act on a child by force of violence, duress, menace and fear."

Mountain View police arrested Carlos Sarceno and Jose Pinto -- both 17 -- along with Pinto's 20-year-old brother, Mario Pinto, in connection with the sexual assault of the young teen, who passers-by found intoxicated at Castro Park at about 9:30 p.m. on Nov. 28. All three alleged assailants were arrested several hours later.

The suspects were arraigned on Dec. 4 and are expected to enter a plea in the near future, according to Clarissa Hamilton, the prosecuting deputy district attorney. Hamilton called the assault "heinous."

"It's a really, really vicious thing to do to another human being," Hamilton said, referring to sexual assaults in general. "Any sexual assault is not good; this one is particularly bad."

The incident began after the victim and the three suspects got together to drink alcoholic beverages, according to Sgt. Sean Thompson, public information officer with the Mountain View Police Department. Sometime after that, the sexual assault occurred.

Hamilton said that it is not clear that the girl was raped in the technical sense. The charge of "lewd or lascivious action on a child by force" covers rape, as well as groping and other sexual acts, she said.

Hamilton said she is confident that her office has sufficient evidence to convict Sarceno and the Pintos of the charges, which also include what is known as a "gang enhancement."

"We will be alleging that they are Surenos," Hamilton said, referring to the defendants, whom she said are associated with the nationwide Hispanic gang.

In order to get a gang enhancement tacked on to a charge, she said she must prove one of three things: that the crime was committed at the direction of a gang member, that the crime was committed to benefit the gang, or that the crime was committed by more than one gang members working together.

"The acts that occurred are particularly heinous," she said, adding that the investigation is not fully complete and it isn't entirely clear what punishment may ultimately be sought.

Previously, Mario Pinto was identified as a 23-year-old, but according to the district attorney's office, he is 20.

Related story:

• Three arrested for alleged rape of 13-year-old

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