Officials at a high school where a student was gang-raped in a courtyard are moving to tighten campus security with the long-stalled purchase of surveillance cameras, powerful lighting and new fencing.

The measures were disclosed as community leaders sought ways to calm outrage over the Oct. 24 attack at Richmond High School that police said may have involved as many as 10 suspects and 20 onlookers who failed to call police.

"Obviously, there wasn't enough security or we wouldn't have had this tragedy happen," said Bruce Harter, superintendent of the West Contra Costa School District.

Administrators have long pushed for the new measures but couldn't find the money until now, Harter said.

A seventh suspect was arrested Tuesday in the attack on the 15-year-old girl after she left a homecoming dance in the industrial enclave near the San Francisco Bay known as one of the nation's most dangerous cities.

'Violence is a wrong choice'
At a rally and candlelight vigil later Tuesday, DeAnna Schlau with the nonprofit Community Violence Solutions read a statement she said was prepared by the victim.

"Violence is a wrong choice. We realize people are angry about this, but let that anger cause change; change that is necessary to keep our children, our neighbors and our friends safe. We thank everyone for their love, support and ongoing prayers," Schlau said.

Hundreds attended the event, which featured songs, prayer and dancing.

Ten chaperones, six site supervisors and four police officers were at the school gym to make sure the dance and nearby parking lots were safe. They thought things were going so well that two supervisors were allowed to leave early, Harter said.